Garden sage: Beware of carpet beetles; silver sagebrush; salt damage

Q: We found a strange plant in our yard — a “volunteer” — and were wondering what it is because it is crowding out something we planted.

A: This is Artemisia cana (silver sagebrush). It’s a native species in the western states and western Canada and a member of the Asteraceae or sunflower family. Some wildlife and livestock will eat it in case you are keeping sheep. Otherwise, it has nice soft silvery foliage that is a good desert adaptation and yellow flowers.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu

Q: I am taking care of two rose bushes and my fertilizing dates have been a month apart. That has not been a problem but now with fall coming on, my question is do I need to fertilize them another time or leave them alone? My last fertilizer dates have been June 27 for one plant and July 27 for the other one. Neither bush has been really great at producing roses this year, but I try to water them thoroughly (45 minutes) every couple days in the really hot part of the summer. Also, should I cut the plants back a lot before winter or not?

A: The answer to your first question is yes, it would be good to fertilize again now. Roses are heavy feeders that need to be supplied with nitrogen and phosphorus. It is better to apply small amounts every six weeks during the growing season beginning after you prune them in January or February and continue until June. Some like to continue fertilizing through the summer at half strength while others give their roses a break until fall. In either case, going back to regular fertilization can begin again in September and up through mid-October.

We recommend watering roses every three to five days in the summer down to 18 to 24 inches. In the spring and fall, you can back it off to every five to seven days and in the winter, every seven to 14 days. There is no need to prune now; you can take care of that in the new year.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu

Q: What is the beetle eating my sweet potato leaves?

A: This is a species of leaf beetle, Chelymorpha phytophagica, that is more specifically a tortoise beetle. They are known to feed on members of the Convolvulaceae plant family otherwise known as the morning glory family. Sweet potato is among almost 2,000 species of vines (mostly), trees, shrubs, and herbs. Other family members include notorious weeds (bindweed and dodder) and these insects may use these as alternate host plants.

The beetles can defoliate and if there is a large population, reduce the vigor of the plants. Since most plants can handle a little defoliation, it is not something to worry about if only small numbers of beetles are seen.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu

Q: I would like to take better advantage of solar power in my garden. What ways are there to do this?

A: There are a few ways that are fairly easy to get started and then if you want to dig deeper, so to speak, you can explore other ways. To start, you might consider preserving your garden produce by dehydrating it in a solar dehydrator. These can be made fairly easily and there are plans to be found on the Internet. You can also use solar irrigation controllers in a garden drip system. If you are interested in more details and possibly some other energy-saving options, there is an Energy Masters course being offered this fall at the Campus Agricultural Center. This course will teach folks how solar PV, hot water and space heating technology work; costs and benefits of off-grid and hybrid PV systems; how to size solar PV for on and off-grid systems and solar hot water systems; local, state, and federal incentives for systems; and lastly, financing options for renewable energy. You can search the Internet for “2015 Arizona Energy Masters Course” for more details.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu.

Q: I’ve been noticing the sycamore trees around where I live look pretty awful. The leaves are pale and curled up. What is causing this problem?

A: The local trees in Tucson are being eaten by the sycamore lace bug (Corythucha ciliata), a native insect, and present across North America. Sycamore lace bugs cause damage to leaves on sycamores as well as London plane trees. These lace bugs are white in color, about 1/8 inch in size, and feed on the underside of leaves on host trees. Adult lace bugs tend to have an almost see-through appearance, which, combined with venation on wings and ridges on their bodies, lends them their common name. The nymphs differ in appearance from the adults in that they are black and spiny. Adults are very mobile and their movement is aided by wind. Lace bugs go through five life stages: egg, three immature or nymph stages, and adult. Adults overwinter in bark crevices or branch junctures, and become active again in the spring when leaves begin to break from their buds. Shortly thereafter, the adults lay eggs on the underside of leaves and eggs hatch within a matter of days of being laid. Nymphs feed on the underside of the leaves as they grow. Nymphs, which are wingless, smaller, and more rounded in shape, tend to cluster together on the underside of infested leaves. Wherever they are feeding, frass (insect feces) may be seen as well. The frass appears as tiny drops, shiny and dark in color. The life cycle is about 45 days in length, allowing for several generations throughout the year.

Early infestations are evident when white spotting begins to occur on leaves where the insects are feeding. Black spots, the frass of the insects, appear widely across the underside of the leaves as well. Heavy infestations can result in bronzing and drying of leaves. Eventually, those leaves will fall prematurely, making trees look to be in poor health. Established trees can sustain this damage for several seasons. Young or newly planted trees experience more adverse effects during infestations than established trees. The damage is more severe as weather patterns bring drier conditions.

Though there are insecticides and other types of management actions that can be taken, most damage is aesthetic. Watering trees properly can help relieve stress on trees. Additionally, strong streams of water on leaves can be effective in removing insects, especially when targeting lace bugs in the nymph stage, before severe damage occurs. However, these infestations do not require any treatment. There are also natural fungi as well as predators and parasites of lace bugs that can help manage populations.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu.

Q: My pyracantha leaves recently started looking like the attached picture. A drip system waters it every three days for 30 minutes. Hasn’t had a fertilizer application since Memorial Day.

A: What you are seeing is salt damage. Salts build up in the root zone from our salty water and from fertilizers. The solution is first to overwater to flush the salt through the root zone and then change your irrigation schedule to water less often but deeper. For non-desert shrubs like pyracantha it is best to water every seven to 10 days to a depth of 24 to 36 inches in the summer, every 10 to 14 days in the spring and fall, and every 14 to 21 days in the winter.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu.

Q: What is this tiny black beetle with orange spots? There are a bunch of tiny black beetles with orange spots in our kitchen pantry.

A: Those are carpet beetles and their larvae you will recognize as tiny, hairy grubs. Often what are found are the cast skins of the larvae from their molts among your damaged things. They are common indoor pests of stored products and other organic materials. Back in the day, when most carpets were made of wool or other natural fibers, these insects got their name. They can be found on a variety of things besides carpets and are most likely infesting something near where you are seeing them in the pantry. These insects are sometimes used by mammalogists to clean animal skeletons in scientific collections. Sadly, they are also a serious museum pest and are notorious for eating insect collections and other dead animals. In your situation, the first things to check are any open containers of pet food, bird seed, etc. Then start working through things stored in cardboard boxes or other easily chewed containers. You might also check if you have any boxes or clothing made of natural materials. The eradication of these beetles is difficult. Sanitation and exclusion are the most important tactics.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu.

Q: Can you identify this insect? It’s beautiful, gentle and somehow makes me think of an acoustic guitar. There are perhaps 30 of them in the main crook of a tree at my home.

Ar: These giant mesquite bugs (Thasus neocalifornicus) are a common sight in desert southwest landscapes, particularly on mesquite trees during May-August. These large bugs commonly aggregate in family groups and look impressive that way with their brightly colored nymphs. Despite their name, they may also be found on other garden and landscape plants.

They cause no significant plant damage, are harmless to humans, and do not have a venomous bite or sting so enjoy these bright highlights on our mesquite trees.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu

Q: I was wondering if you could help me out with another insect ID. I have this tree that crashed and while inspecting it found what appears to be insect holes and the insect attached. Is it possible for this insect to affect a tree?

A: This is an uncommon beetle without a nice common name. I checked with our identification expert, Gene Hall, in the entomology department on campus to be sure since I hadn’t seen one before. The scientific name of the beetle is Trimitomerus riversi and it belongs to the insect Family Pythidae — Dead Log Bark Beetles.

This species, the only one of the genus found in North America, is restricted to Southern Arizona. While adults have been collected, the larval stage and life cycle of this beetle is unknown. Larvae of other species in the Pythidae family have been collected in the subcortical of dead conifers, deciduous logs, or sapwood of rotted conifers.

There is still much to learn about the natural histories of this group so getting an identity is the best we can do for now. With upwards of 70 million insect species out there and a little over one million described, we occasionally find one that we don’t now much about. The family descriptor, dead log bark beetles, makes me think you have nothing to worry about.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu

Q: What are these little gray buggers on my sunflower leaves?

A: They are lace bugs, small plant bugs that suck plant sap from the leaves. They are often found on the underside of leaves. The grayish ones are the adults and the smaller, blackish ones are the nymphs. The smallest black spots are their frass (poop). On sunflowers, we just let them be because they might damage the leaves but the flowers are unaffected and the plants seem to tolerate them to some extent. Other plants are not as tolerant. If you wanted an organic solution you could try insecticidal soap, horticultural oil, or a pyrethroid such as PyGanic.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu

Q: About 1 ƒ years ago I purchased four white flowering oleander plants—the tall not the petite variety. They have been deep watered regularly, fed in May and have only grown about 1/16th of an inch. They have original leaves, have flowered but have no new growth or leaves. My hope was these would grow quickly in front of my screened in porch. I have other oleanders in the back and side yards that are huge, some of which I have planted. I wonder if the soil is old as I have lived here 31 years and the home was built in 1968. There had been huge juniper trees that died over the years. Perhaps this area of soil is not rich enough to support new growth. I’ve considered moving the oleanders and putting in birds of paradise.

A: Many woody plants will take up to three years to grow a lot after planting so I think you should give it more time. Another factor could be the roots of your old junipers. If they were cut down recently and simply cut at the soil level, the stump and roots are still in the ground. That means the roots will decompose over time and in the process take nitrogen from the surrounding soil for that process, leaving less for your new plants. Not knowing the exact situation with your junipers, I am doing a little guesswork here so it would be good to have more information about the timing of their demise and the planting of your oleanders. Having your soil tested is a good idea if you are still concerned about this. There are a few labs in the area that will test it and you can call the Pima County Extension Office to ask for their contact information.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu

Q: We recently came back to Tucson from a week in San Diego to find about a hundred or more June bugs on our mature fig tree. We have lived here for over 20 years and this has never happened before. Is there any reason the bugs would be swarming on the figs at this time? Is there any safe way to get rid of them?

A: These insects are attracted to ripe figs and other fruit. They feed on the juice as adults and live in the soil as grubs. Often they attack fruit that has been damaged by birds pecking holes. We occasionally have a large population of beetles and they don’t always show up on the same plants each year.

There are some organic pesticides you can use but they are not very effective against the adult beetles. In addition, since there are so many of them, you can’t get them all and they fly away when you try. I suggest picking the fruit if it is ripe and protecting it with bags if it is not ready to be picked and you plan to eat it.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu

Q: I have many Penstemon parryi seedlings that have been growing through the summer. Within the last two weeks they have begun to develop “burned” scale patches on the leaves that are accompanied by black “seedy” areas. The black beads could be the seeds for future plants, except that these haven’t ever bloomed. The black beads don’t appear to be adult insects, but could be eggs. Do you have any idea what’s going on?

A: Very small caterpillars, the chalcedon checkerspot (Euphydryas chalcedona) most likely, are eating your Penstemon plants and the black “seeds” are actually caterpillar poop or frass as we call it when it comes out of insects.

The plants will likely be OK regardless and you are supporting a healthy butterfly population but if you see active caterpillars chewing your plants to the ground you can spray the leaves with Bacillus thuringiensis, aka Bt. This organic compound will make the plant poisonous to the caterpillars that eat it and will not harm other organisms on the plant. There are multiple strains of Bt, so if you choose to buy some, make sure you are getting the strain designed to kill caterpillars.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu.

Q: We have tons of mesquite pods and they are a huge pain. A yard guy we met said he could spray the tree next April and that would take care of it. Then I read that spraying doesn’t work well on Mesquites because the timing has to be accurate and the pods mature over too broad a time period. Also, our tree is huge and I worry about the spray harming nearby plants. What do you say?

A: The spraying doesn’t work well on most trees, it is costly and time consuming, and it could harm surrounding plants and other organisms, depending on the chemical used and if not done correctly.

There are many factors at play including timing, environmental conditions, and making thorough applications. Due to the gradual development you mentioned, it might take repeat sprays to do a sufficient job. It would likely be more environmentally sound and cheaper to hire someone to rake the pods. Another alternative is to harvest the pods before the monsoon begins and have them milled into mesquite flour. Mesquite flour is a popular alternative to wheat flour among local and heritage foodies and a nice gluten free alternative for those that require one in their diets. Milling events are available in various locations during the harvest season and they charge a nominal fee to grind them for you.Check out DesertHarvesters.org for one group that does this and instructions on how to harvest.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu.

Q: What are the luminescent critters found in the Tucson region? Back East there are fireflies or lightning bugs, but I have not seen them here.

While taking a predawn hike in Sabino Canyon several years ago, we spotted a small wingless luminescent crawling insect on the roadway. It was about a half inch long with a termite-like appearance, and put off a light bluish light. A few dark nights ago looking out past our back fence line on the ground I spotted my second luminescent critter, I think. It was an LED-like spot of white-bluish light that persisted for several minutes. Our home is at about 2,750 feet in elevation in north Tucson. Any suggestions as to what we are seeing? Sober on both occasions.

A: Lightning bugs are one of my favorites from back east. We used to feed them to toads and watch them light up in their bellies, making the toads glow. What we have in the West are a couple dozen other species, although none as common as the ones back East.

What you were likely seeing are the immature beetles of one of these species. According to retired bugman Carl Olson, now is a great time for people to see the larval stage that usually has an eerie green light. Most of the ones seen in Rincons and Catalinas are pink as you will see in his photo of Microphotis dilatatus from the Vail area.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu.

Q: I am starting to see some odd growths on parts of my oleander hedge. I understand they are galls but I am not sure what to do about them.

A: Oleander (Nerium oleander) is one of the most popular evergreen shrubs in Arizona and the gall disease you are seeing is widespread. Oleander gall is caused by the bacterium Pseudomonas syringae savastanoi.

The galls occur on twigs, branches, leaves, flowers, and seedpods. Initially galls appear as small protuberances that subsequently develop into wart-like growths with roughened, fissured surfaces. Galls vary in size but average about a half to 1 inch in diameter. Large galls are usually made up of several small galls that have grown together.

Galls are the result of the growth and multiplication of the bacterium. The bacteria enter and infect oleanders through leaf and blossom scars, wounds produced by pruning, frost injury, and natural openings. Rain, sprinkler water, and pruning tools can spread bacteria from diseased to healthy plants.

When purchasing oleanders, examine them carefully to be sure they are free of galls. The vast majority of nursery stock is free from disease but prevention is always the most effective method of disease control. For diseased oleanders, prune out infected plant parts and apply disinfection solution (a 10 percent solution of household bleach) to each cut surface.

Always dip pruning tools in the disinfectant solution between cuts to reduce the possibility of spreading the bacteria. Pruning operations should be conducted during the dry seasons to avoid infection of wounds. Avoid sprinkler irrigation. Severe infection of large shrubs is difficult to control by selective pruning. If the entire shrub is cut down, the new succulent growth is extremely susceptible to infection. In certain situations, removal of the diseased plant and replanting may be the best method of control.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu.

Question: I have a front yard without a fence or wall. I’d like to line it with bird of paradise bushes. Can I use a cutting to start them growing or do I have to use seed? And if so, when would be the best time to plant?

Answer: You can propagate bird of paradise (Caesalpinia species) by seeds, cuttings, simple layering or dividing plants. Softwood cuttings can be taken in the spring and early summer. Sever the stem between the leaf joints or nodes, just below a node. You may want to use a rooting hormone to encourage the roots to develop. I have a publication on these plants in case you are deciding which variety to plant. You can look for the publication by searching online for the publication number “AZ1634.”

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu.

Question: I have 13 rose bushes in my backyard against the side concrete wall that were planted two years ago. The first and second years they really grew and blossomed nicely. But this year, for whatever reason, all the petals are dropping off and most of the bushes are now bare. Because of the warm weather this winter, they seem to have bloomed much earlier than usual (in March). I am wondering if they will have a second blooming season this year before “winter,” and what could be causing the petals to fall off. They are very delicate, it seems.

Answer: A common problem with most plants is lack of water. Plants often lose parts when they are too dry, and yours are most likely receiving additional heat radiation from the wall. Roses typically require water every three to five days in the summer, every five to seven days in the spring and fall, and every 14 to 21 days in the winter. And you should be watering to a depth of 18 to 24 inches.

Roses also need to be fertilized. It is better to apply small amounts of a slow-release fertilizer every six weeks during the growing season rather than a heavy application once a year. The first application of slow-release fertilizer should be applied after the roses have been pruned in January or February and repeated every six weeks until June.

March is about right for roses to begin blooming in Tucson if you pruned them in late January. At our office, the Rose Demonstration Garden maintained by the master gardeners started blooming in late March and bloomed into April. Some of them are still blooming. Yours will likely have a second bloom in the fall if you prune them again in mid-September. For more details, check out our publication available on the Internet by searching for “roses AZ1305” with a search engine.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu.

Question: What can I use to finally get rid of these stubborn desert broom weeds once and for all?

Answer: Desert broom (Baccharis sarothroides) is typically seen as an invasive native shrub but opinions differ on its status as a weed or just part of the desert flora. The phrase “invasive native” seems like an oxymoron but this plant has a habit of moving into disturbed areas as new construction or other changes to the desert soil occur, so it is certainly an opportunistic native plant. My predecessor, George Brookbank, has written that it can be used as a hedge because it can reach 10 feet in height and is almost always green. It also provides habitat for birds and other organisms.

There are cultivated varieties used in landscape plantings that are prostrate in form. Even these are reported to revert to the native species when they reseed. The way to get rid of them is to use an integrated approach. Since they propagate by wind-blown seed, you will start to see new seedlings in the spring. Pull these up as you find them. Once they become established their roots go deep and are harder to remove. Mature plants can be cut down near the soil surface. Spraying or painting the freshly cut stump with glyphosate herbicide may stop the regrowth. If it comes back from the stump, spraying the new green growth with the same herbicide will allow the active ingredient to translocate to the root zone, where it may kill the plant. Repeated applications may be necessary.

There is no way to eradicate these plants; we can only hope to contain them as landscape plants or manage them away from desired locations. As with any pesticide, make sure you read the label before you apply and follow all safety precautions listed to protect yourself and the environment.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu.

Q: Here is a picture of a new plant sprouting up in my yard. Is it a weed or something nice? Will it grow tall? Leave it or yank it? Thanks.

A: It is called tree tobacco (Nicotiana glauca). Tree tobacco is a slender, erect, straggling shrub or small tree growing 6 to 20 feet tall. Tree tobacco produces sprays of nodding, tubular bright yellow flowers and is a prolific seed producer. Opinions differ on its status as a weed or ornamental. It is a bit stinky and the plant parts are toxic to animals like some other plants in the Solanaceae plant family so you should keep children and pets away from it. I have a friend that likes the yellow flowers they produce and keeps it around for that reason.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu.

Q : Recently I noticed, on two mesquite trees, a tarry-looking seepage coming out, and in some cases dripping onto the ground. What is it, and what if anything should be done about it? The only thing I can think of regarding care of the trees that might have some bearing on the matter is that they were not watered this spring, and in fact have been without significant (added) water for several months, and have looked a bit less robust than usual this spring in terms of leaf output.

A: What you are seeing is called bacterial wetwood or slime flux. Slime flux is caused by the infection of sapwood by several bacteria and is a problem with mature mesquites. The disease-causing microorganisms are found in the soil and probably gain entry above or below the soil line through wounds or pruning cuts. After several years, affected areas will exhibit a water-soaked appearance (wet wood). Gas is produced by the bacteria (and possibly yeasts) that force out a foul smelling liquid from cracks and wounds. The liquid is dark brown to black in color.

Infected trees live many years and slime flux is more of a nuisance that requires periodically a strong, hard stream of water to prevent staining of patios and cars. Seriously infected branches may need removal if they present a safety hazard. The old remedy of placing drainage tubes into the infected areas is not recommended, and may in fact, present more entry sites for the disease.

Regarding the water schedule, I recommend a good soak of the root zone out near the edge of the crown of the tree every three weeks during the growing season down to about 36 inches. Of course you can hold off during the monsoon season if you get good rains and during the winter as well.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu.

Q: After 12 years my toothpick cactus has finally yielded five flowers for the first time. I am wondering if I could propagate a toothpick cactus, and if so how do I do it?

A: You can propagate the toothpick cactus (Stetsonia coryne) by seed or cuttings. For cuttings you simply cut off a section from the top of a stem using a sharp knife and at a 45-degree angle to protect the parent plant from water collecting on the wound. The size can be anywhere from three inches up to six feet. Square off the cutting, dust with sulfur and/or a rooting compound and leave in a dry airy place to form a callus. This can take one to four months, depending on the weather. August through October is a good time of year to do this part. Next, pot the cutting using standard cactus mix containing 50 percent pumice or perlite and 50 percent peat or compost.

Plant it deep enough that it won’t fall over, filling in with fine gravel to hold it steady. Water once a month or so to keep the mix from completely drying out but avoiding the risk of rot. Leave the pot in a bright spot.

The cutting should root in a month or two although some take longer. Once the cutting is showing signs of active growth you can remove it from the pot and transplant it to another larger one or to the ground where you want it to grow. There is no hurry if you use a one- or two-gallon pot. They can grow in that for up to a year.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu.

Q: I have two ocotillos that I planted myself about seven years ago. Both are oddly shaped but growing well from their original size of about 1 foot. They grow 6 to 10 inches a year, green up at the appropriate time but neither has ever bloomed in the spring. They are not on drip but one is near a drip line and the other is not. I water them very occasionally. I have tried fertilizing and not fertilizing. It seems to have no effect. What can I do to encourage blooming? The tallest branches on them are about 7 to 8 feet tall.

A: Ocotillos (Fouquieria splendens) are tough plants and can usually be counted on for blooms in the spring. Because these plants have the ability to put on leaves when there is sufficient water and drop them when it is dry we call them drought deciduous. Their ability to produce flowers is likely also related to available water so you can keep an eye on how often they leaf out to see if they are doing well.

The main factors for blooming are the age of the plant and the number and length of branches that are reproductively active. These are obviously not something we can control so your best bet is to make sure it is otherwise healthy by watering appropriately. That means every 14 to 21 days down to 24 to 36 inches in the spring, summer, and fall. In winter, you can skip the irrigation and let nature take its course. These plants do fine without fertilizer in their native habitat unless you are planting it in a container.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu.

Q: About three years ago, I lopped off the top of a pineapple purchased at a local grocery store and planted it. In April, my first pineapple began to grow. It appeared to be growing at a good rate, when it began to yellow. When checked, I found that something (bird or bug) had drilled several holes into it, causing it to die. Do you know what caused the damage and how I can avoid it in the future?

A: From the photo you sent, I suspect it is bird damage. Insects will come to the holes made by birds for the juice so you may find them there as well. The best way to prevent this is to exclude the birds once the fruit begins to develop. You can accomplish this with hardware cloth around the whole plant or you can enclose the individual fruit in a breathable bag as people do with peaches and grapes.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu.

Q: I live in Oracle and have a native oak with ivy growing up the trunk. I am wondering if it is a threat to the tree. I also have a mature netleaf hackberry covered by a native grape and another oak with a passion vine rapidly climbing to the top. Should I try to control any of these vigorous vines?

A: English ivy (Hedera helix) is in the ginseng family Araliaceae and it is the most troublesome ivy for trees and other landscape plants in a large part of the U.S. It is an aggressive plant that can rob trees and other plants of resources by climbing over them to seek sunlight and invading their root zones with their own to seek water.

However, it doesn’t typically do well in the desert. The trouble for English ivy here is the hot temperatures and dry, salty soil we typically have in southern Arizona. Your location in Oracle is probably just cool enough to allow it to survive in the shade with sufficient water. I doubt it would kill the tree but it could reduce its vigor. So with suitable habitat for English ivy and if it is doing very well, I would recommend cutting it back or down from the tree. Severing it at the base is probably all you need to do to keep it in check. Otherwise, you have a nice specimen of a vine that isn’t often seen here. The native Arizona grape vine (Vitis arizonica) is not typically a species we call a weed and worry about managing but if you find it growing so vigorously it covers a desirable tree or shrub, you could cut it back or out. Like many other vines, it seeks the high ground to get sunlight and can shade out other plants. Passion vine (Passiflora foetida) is often considered a desirable ornamental vine with beautiful flowers that is great for attracting butterflies so I wouldn’t worry about that one unless it compromises a tree you like better.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu.

Question: I’m sorry to bug you again, but I can’t think of anyone else to ask. When I have been going out in the backyard, in the dirt there are dozens of tiny craters. They are perfect, about an inch deep, and inch wide, and perfectly circular. Something is making them in the night, what can it be?

Answer: The craters are like tiny pitfall traps and each contains a doodlebug at the bottom under the sand. They are supposedly called doodlebugs because of the way they doodle in the sand while they meander about. They are young antlions, a kind of predatory insect of the family Myrmeleontidae. If you know your ancient Greek, the translation is easy (myrme = ant, leon = lion). They sit in the bottom of the cone shaped hole waiting for unsuspecting ants to fall in and then they eat them. Interestingly, these insects make their cone shaped traps using the steepest angle the sand can maintain that shape so that the slightest disturbance will cause the prey and the sand to fall to the bottom where the antlion waits, jaws up, for supper. It can be cheap entertainment for kids if they like to manually put ants into the holes and watch the carnage. That’s what we did. Caution: playing with insects is habit forming and they might grow to be entomologists like me.

Q: These bugs are eating my morning-glory plant. Can you please tell me what they are and how I can get rid of them?

A: Those are tortoise beetle larvae. I mentioned the adults in a July column. This is a nice photo of the young ones. They resemble Mexican-bean beetle larvae with their yellow bodies and spiky appearance. They are plant-feeding beetles and can be an occasional pest on a variety of vegetables and weeds.

The good news is the vegetables and other plants can handle the holes in the leaves that they make so you really don’t need to do anything to manage them. More good news is that these insects are helpful in keeping some weeds in check and have, in some cases, been raised and released to manage specific weed species.

If they were a small population, I wouldn’t worry about them. If you are concerned they are getting too numerous on your plants, you can simply knock them into a bucket of soapy water.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona.  Questions may be emailed to plwarren@cals.arizona.edu.

Q: I live in the Marana/Tucson area and would love to grow wine and table grapes. I have a wash behind me and I have a wall around my back yard. What my chances are of growing my own grapes on trellises?

A: Your chances are good. Probably the most abundant grape variety for Southern Arizona is Thompson seedless. It’s one of the most popular grapes for eating fresh, with a sweet but mild flavor. The berries are medium-size and the clusters large with greenish white to golden berries. Thompson seedless is the variety most often used for making raisins. Other recommended table grape varieties include cardinal (dark red berries), perlette (pale green berries) and flame seedless (red berries).

If you’re interested in making wine, several European wine grapes also grow and produce well in our area. Some of the best reds for our hot climate include shiraz, petite sirah, barbera, tempranillo and cabernet sauvignon. Recommended white wine grapes include sauvignon blanc, Viognier and pinot grigio.

Grapes should be planted in full-sun locations and well-drained soils. Test the drainage by digging a hole 12-inches wide and 18-inches deep. Fill the hole with water and let it drain. Fill it a second time and observe how long it takes for the water to drain from the hole. If the water drains out in 48 hours or less, the soil has adequate drainage for growing grapes.

Grapes can be purchased from local garden centers in containers or bare-root from mail-order nurseries. Container-grown grapes can be planted spring through fall. Bare-root grapes are ordered and planted during the winter months.

Regardless of the type, grapes should be planted directly in unamended soil. No organic amendments should be added at the time of planting. Just dig a hole large enough to accommodate the roots, removing any stones or caliche from the hole. Loosen the soil and fill in around the roots.

Grapes can be trained to grow on trellises, arbors or single posts. If you’re planting several grape vines it’s best to build a trellis using 4-by 4-inch wood posts or heavy metal T posts spaced 15 to 18 feet apart. Two heavy-gauge wires are attached to the posts, the first at 36 inches above the ground and the second at 60 inches above the ground. The first wire is used to train the fruiting cane, called the cordon. The upper wire is there to support the fruit-producing shoots.

The most effective method for training and grape production is the unilateral cordon system where grapes are planted 6 feet apart and trained to grow in one direction down the trellising wire. The first growing season, a single shoot is selected to grow up a small supporting stake to the trellising wire and then down the wire in one direction. The grape vine is attached to the support stake and wire with Velcro plant ties or plant tape. In the second season, fruiting spurs are developed every 4 to 6 inches along the vine.

Drip irrigation works best for grapes, with two 1-gallon drip emitters placed on either side of each grape plant. Grapes need ample water, especially during the first two or three seasons as they are becoming established. After establishment, grapes will need regular watering from two to four times weekly during the growing season and fertilization with a high nitrogen fertilizer in early spring and in the fall.

Q: When my car was serviced a couple of days ago a large black widow and her nest fell on the technician. He took it down and we sprayed under the car but I’m concerned there are some inside the car. Also, I’m wondering how one would be nesting under my car. My car sits in a carport and is driven almost every day. What can I do to keep this from happening again and make sure they aren’t in the car?

A: It would be good to see the nest to know if any hatched but I bet from your description that you disposed of it already. Spraying under the car may have taken care of any young ones crawling about. Mothers will stay near to defend their egg sacs and the young spiderlings stay close by her soon after they hatch. Then they go ballooning away to start their own webs in a new spot if they survive and most do not.

It is not easy to keep insects, spiders, and even rodents out of vehicles. They are excellent shelters against the environment, especially when shaded as yours is by the carport. Parking in the sun could be a benefit in this situation since it would get very hot inside and probably not be a good habitat for anything for very long.

We can sometimes screen out rodents but smaller animals are more difficult. The best way to keep them out is to make the area around your carport less hospitable so they have farther to go to seek shelter. This can be accomplished by keeping the surrounding area clear of any plant material, be they ornamental plants or weeds, and other objects that could also act as a shelter such as a woodpile or a storage shed.

Q: Can you tell me about the cute praying mantis that has been on our sesame plant for several months now.

A: Praying mantids are highly predacious and feed on a variety of insects, including moths, crickets, grasshoppers and flies. They lie in wait with the front legs in an upraised position. They intently watch and stalk their prey. They will eat each other. Praying mantids are often protectively colored to the plants they live on. This camouflage facilitates their predaceous behavior. Mantids are usually found on plants that have other insects around. Some mantids live in grass. Winged adults may be attracted to black lights in late summer and early fall.

Many fish and predatory aquatic insects eat larvae and pupae. Bats, birds and spiders eat flying adults. The adult female usually eats the male after or during mating. Mantids have a grasping response that is incredibly rapid, so that you see it before it catches the insect and when the insect is in its front legs. The motion is barely a blur if it is perceived at all. Mantids are active predators and consume other insects.

They are good garden predators, but are cannot keep up with the population growth of some insect populations and do not discriminate between beneficial and harmful garden insects.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu

Q: I am planning on planting ocotillo before the end of this monsoon season; any advice/instruction?

A: Ocotillos are planted much like any other shrub. Select a spot that will allow for the mature size of the plant and in an area with like plants that have similar water needs to make irrigation simpler. Dig the hole to be as deep as the roots but no deeper so it won’t be planted too deep. Fill the hole with native soil and water. If the watering makes the soil sink a bit around the planting hole, you can add more soil and maybe a few rocks around the edge for stabilization.

If this is a small plant now that should be all you need. If the plant is much larger and not able to stand on its own from the start, you might need to stake it. Three stakes around the plant are best, tying each one to a large cane.

Don’t make the ties so tight that there is no room to move a bit in the wind because a little movement is how the plant will develop its own stabilization over time. Typically stakes are left in for one year although it may require a bit longer depending on the size of the plant and the growing conditions.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu

Q: Now this is a bug! What the hell is it? Eerily beautiful and frightful at the same time.

A: What you have is a whip scorpion. The only whip scorpion found in the United States is the giant whip scorpion, Mastigoproctus giganteus. The giant whip scorpion is also commonly known as the vinegaroon. To encounter a giant whip scorpion for the first time can be an alarming experience so I understand your fright. What seems like a monster at first glance is really a harmless creature.

Whip scorpions are found in the southeastern oak zone of Arizona east across the southern U.S. to Florida. They have a substantial but flat body 2-3 inches in length, with large spined, arm-like pedipalps in front. They are arachnids but have no venom. Whip scorpions are predators, active at night. The whip-like tail is used in defense and individuals can squirt acetic acid (vinegar) produced from a gland in the rear, hence their nickname: vinegaroon.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu

Q: Can you tell me something about the weed called funastrum twine vine?

A: The plant in question is considered a weed to some and an ornamental plant to others. As we like to say, a weed is a plant out of place or a plant whose economic potential has yet to be realized. Funastrum cynanchoides, otherwise known as fringed twinevine, climbing milkweed vine, and twine-vine is in the Asclepiadaceae or milkweed family. It is a smooth vine with umbels of pale white, star-like flowers and long twining stems often clambering over tops of bushes. It has milky sap, hence the name, and is a food plant for caterpillars and several species of butterflies including monarchs and queens. There are several similar species in the Southwest, all hairy or downy and with foliage that smells somewhat like hot rubber. Its native distribution is Southern California east through southern Utah to Oklahoma and Texas, and south to Mexico. It’s native habitat is chaparral and brush country and open woodlands. It requires a moderate amount of water, part shade, and can survive in a variety of soil types.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu

Q: Any instructions for planting a bougainvillea in Green Valley? I will purchase a potted plant and put it in a hole in the ground.

A: Bougainvillea is a tough plant and digging a hole that is as deep, but not deeper than the roots in the container is the main thing. You can set the container in the hole once you think it is deep enough to make sure. The main things to watch out for when selecting a site are protection from the cold and proper irrigation. In Green Valley, there is a greater chance of frost damage, and this plant can die back to the ground. So choosing a site that is somewhat protected or close to hardscaping that can radiate heat is helpful. In extreme cold, you may have to cover it like we do with citrus. Also this plant doesn’t need much water but it does need some, especially to get established, so make sure there is a way to get drip irrigation or hand watering to the plant.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu

Q: We’ve had this plant in our yard for at least seven or eight years, and this year it sprouted this unusual branch. It’s about 1.25-inches wide and the thickness of a normal “round” branch. We have never seen this before. Is this normal? Or is there something wrong with this plant?

A: The odd branch is not normal but it’s also not a big deal. We call it fasciation and it is abnormal growth in which the growing tip becomes elongated perpendicularly to the direction of growth producing flattened, ribbon-like or crested tissue. Some plants have mutations like this periodically and are prized aesthetically for this feature.

You might occasionally see saguaro cacti with this fasciation. We have one on campus near Old Main that draws a lot of attention. Viruses, mites, or environmental factors sometimes cause the mutations.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu.

Q: We planted two different kinds of tomatoes in a planter. The larger variety is thriving. The smaller variety has tomatoes that grow in green and no problems, but as they begin to ripen, the end farthest from the stem turns black.

A: The problem you described is called blossom end rot and it is associated with a calcium deficiency.

While the occurrence of blossom end rot may indicate calcium deficiency, in reality, the soil may have adequate calcium. However, for various reasons the plant may not be able to take up enough calcium to supply the rapidly developing fruit. As a result, efforts to manage this problem fall into two categories: pre-plant and post-plant.

Prior to planting, the main preventative measure is to have a soil test done to determine if there is adequate calcium. Limestone (a source of calcium) should only be applied if soil test results recommend it. When limestone is needed, best results are achieved when the limestone is worked into the soil 2 to 3 months prior to planting.

After tomatoes are planted, you can minimize the potential for blossom end rot by doing the following:

Once transplants become established, encourage the production of a large root system by keeping plants a little on the dry side for a few weeks (until they begin to flower and set fruit). A large root system is better able to take up the calcium needed for the healthy development of the tomato fruit.

After fruit set begins, keep soil evenly moist. (Avoid extreme fluctuations in moisture levels. Do not overwater!)

Apply a layer of mulch to help maintain even moisture and keep soil cooler.

Do not over fertilize. Especially avoid high-nitrogen fertilizer as it can cause problems with the uptake of calcium.

Do not cultivate closer than 1 foot to plants to avoid damaging roots.

If tomatoes develop blossom end rot, spray the foliage with calcium chloride or calcium nitrate when symptoms first appear. Follow the instructions on the label. Removing fruit with symptoms is also recommended.

The good news is that tomato plants self-adjust after the first fruit are set, and later fruit are typically not affected by this disorder.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu.

Q: I have at least four chuckwallas living in my backyard. I have identified them using photos on the Internet. They range in size from 6 to 14 inches. They are eating the leaves of my vegetable garden. How do I make them leave my yard?

A: The chuckwalla (Sauromalus obesus) is a resident lizard in these parts so your yard is also its yard. You can’t stop them; you can only hope to contain them. Your best bet in the case of any four-legged varmints eating your vegetable garden is to exclude them using a barrier so they cannot access your vegetables. Since these are relatively large lizards, hardware cloth and PVC pipe, or a reasonable facsimile thereof, can be used to fashion an enclosure they cannot penetrate that you can lift off when tending your garden.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu

Q: I planted a Bearss Lime tree about five years ago. When we had the bad freeze a few years ago it froze. Since then it has come back and has grown very well. However it never produces. I fertilized this year. It had blossoms but no limes. Can you suggest a remedy? I also water it regularly.

A: It seems you have the basic care strategy down but maybe it could be tweaked to be more effective. To start, we recommend fertilizing citrus three times per year: January/February, April/May and August/September. The amount of fertilizer you use should be based on the type, age and size of the tree. We have a chart you can use by searching for “University Arizona citrus fertilizer” on the Internet.

Watering should be done every seven to 10 days to a depth of 36 inches in the summer. In the spring and fall you can back off to watering every 10 to 14 days and in the winter, water every 14 to 21 days. This is for citrus planted in the ground. If your tree is in a container, you will have to water more often and base that frequency on how fast the soil dries out.

Bees and the wind will accomplish most of the pollination of citrus flowers. If you are not seeing any bees on your citrus flowers that could be a problem. Making sure you have an attractive habitat for bees by planting other flowering plants nearby is helpful as is providing a water source. Also keep in mind that citrus produce more blossoms than fruit.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu.

Q: I have two mature olive trees in my back yard. They do not fruit. I would like to know how much to water them especially now in the hot Tucson summer. Also both have sprouted suckers and I am not sure how or when to prune these.

A: Olive trees need water every seven to 14 days to a depth of 24 to 36 inches during the summer. In the spring and fall you can back off to every 10 to 21 days and in the winter every 14 to 21 days.

You can prune suckers any time. The way you prune them is close to the branch they are growing from without leaving a large stub or going too close to the branch so as to make a cut flush with the branch surface. There is a nice publication at the UA that provides illustrations of these cuts. You can search for it by using the publication number AZ1499. If the suckers are coming from under ground, prune at the ground level.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu.

Q: My tomatillos are full of holes and I can’t figure out what happened. What should I do to prevent this next time?

A: The culprit that damaged your tomatillos is the tomato fruitworm (Heliothis zea) aka the corn earworm. This is a common pest of these plants across the U.S.

Spinosad (many brands) works well on moth larvae like the tomato fruitworm, but it does nothing once larvae are already within the fruit. In your case, they are already finished and moved on to pupate in the soil. If you start seeing fruitworms in tomatoes or tomatillos, start applying spinosad every five to seven days through harvest. Focus on fruits higher up and on the outside of the plant where females prefer to lay eggs. Spinosad may be applied up to one day before harvest. Since your tomatillos are already affected, make note of when you started seeing the damage so you can be prepared a few weeks in advance for the next crop.

If you have any corn still in the silking stage, you can prevent corn earworm larvae from entering the corn by spraying (or rubbing) the silk with one part Bacillus thuringiensis (many brands) to 20 parts pure oil (mineral, corn, or soybean). Start this treatment when pollination is almost complete, which is when the silk tips have begun to wilt and turn brown.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu.

Q: I have a fig tree and a pomegranate that I planted in 2012 in water harvesting basins. They both were thriving and last year I got great harvests from both with large and juicy fruits. They got supplemental water but mostly they got water two times a day from drip irrigation for 30-40 minutes in the a.m. and p.m. This year the fig got a lot of fruit but they were small and sort of dry, the pomegranate also got fruit but they are small and lots of them have split right in the middle and they have not reached maturity. The fig’s leaves were also turning yellow with some brown tips and falling off.

A: These trees do better with deep, infrequent watering instead of a little bit each day. The brown leaf tips are a sign of insufficient water and possibly salt damage from underwatering. The cure is to provide more water to wash the salt through the root zone. The small fruit and splitting could be attributed to the watering issue as well.

I am not sure how long ago you switched to the new watering schedule. It might take a while for the trees to show a lot of progress. This being their third year in the ground should have been the year they take off but they might have been set back a bit by the lack of water in the recent past. I say keep up the new watering schedule and see how they do.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu.

Q: I’m pretty sure my palo verde tree is suffering from major beetle damage. Many branches are dead, it barely leafed out, and there are many holes in the ground that are very deep. I will take advantage of the holes and do deep watering, but what else can I do to save it?

A: I think you need to have your tree pruned to remove the dead and damaged branches. I recommend using an ISA-certified arborist so the quality of the work is more or less guaranteed. The International Society of Arboriculture has a web site (www.isa-arbor.com) that allows you to search for arborists in your area. The palo verde beetles you collected are very commonly seen during the monsoon season and not a big concern. If the tree is healthy, it should be able to withstand a few beetles. They likely made the holes you are using. Good irrigation is critical to maintaining the health of your tree and watering is best done with a drip irrigation system on a timer so you can accomplish it on a schedule and more efficiently. Desert trees like this need a good soak once every two to three weeks in the summer down to about 24 to 36 inches. It’s important to put your irrigation emitters around the root zone near the outside of the crown of the tree so it reaches the absorbing roots.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu

Q: We have tons of mesquite pods and they are a huge pain. A yard guy we met said he could spray the tree next April and that would take care of it. Then I read that spraying doesn’t work well on Mesquites because the timing has to be accurate and the pods mature over too broad a time period. Also, our tree is huge and I worry about the spray harming nearby plants. What do you say?

A: The spraying doesn’t work well on most trees, it is costly and time consuming, and it could harm surrounding plants and other organisms, depending on the chemical used and if not done correctly.

There are many factors at play including timing, environmental conditions, and making thorough applications. Due to the gradual development you mentioned, it might take repeat sprays to do a sufficient job. It would likely be more environmentally sound and cheaper to hire someone to rake the pods. Another alternative is to harvest the pods before the monsoon begins and have them milled into mesquite flour. Mesquite flour is a popular alternative to wheat flour among local and heritage foodies and a nice gluten free alternative for those that require one in their diets. Milling events are available in various locations during the harvest season and they charge a nominal fee to grind them for you.Check out DesertHarvesters.org for one group that does this and instructions on how to harvest.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu.

Q : Recently I noticed, on two mesquite trees, a tarry-looking seepage coming out, and in some cases dripping onto the ground. What is it, and what if anything should be done about it? The only thing I can think of regarding care of the trees that might have some bearing on the matter is that they were not watered this spring, and in fact have been without significant (added) water for several months, and have looked a bit less robust than usual this spring in terms of leaf output.

A: What you are seeing is called bacterial wetwood or slime flux. Slime flux is caused by the infection of sapwood by several bacteria and is a problem with mature mesquites. The disease-causing microorganisms are found in the soil and probably gain entry above or below the soil line through wounds or pruning cuts. After several years, affected areas will exhibit a water-soaked appearance (wet wood). Gas is produced by the bacteria (and possibly yeasts) that force out a foul smelling liquid from cracks and wounds. The liquid is dark brown to black in color.

Infected trees live many years and slime flux is more of a nuisance that requires periodically a strong, hard stream of water to prevent staining of patios and cars. Seriously infected branches may need removal if they present a safety hazard. The old remedy of placing drainage tubes into the infected areas is not recommended, and may in fact, present more entry sites for the disease.

Regarding the water schedule, I recommend a good soak of the root zone out near the edge of the crown of the tree every three weeks during the growing season down to about 36 inches. Of course you can hold off during the monsoon season if you get good rains and during the winter as well.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu.

Q: Can you identify this insect? It’s beautiful, gentle and somehow makes me think of an acoustic guitar. There are perhaps 30 of them in the main crook of a tree at my home.

Ar: These giant mesquite bugs (Thasus neocalifornicus) are a common sight in desert southwest landscapes, particularly on mesquite trees during May-August. These large bugs commonly aggregate in family groups and look impressive that way with their brightly colored nymphs. Despite their name, they may also be found on other garden and landscape plants.

They cause no significant plant damage, are harmless to humans, and do not have a venomous bite or sting so enjoy these bright highlights on our mesquite trees.

Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu