Q: My tomatillos are full of holes and I canβt 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.
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 βUniversity Arizona citrus fertilizerβ 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.
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.
Q: I am having a problem with my almonds and have had the same problem for the past couple of years. I believe it starts with a leaf-legged bug that causes the fruit to secret sap, and within days the punctured area has this hole where the almond has been removed. Can you help me find what kind of pest is causing this and how to get rid of it? The tree has gone from producing bags of almonds to just 12 total last year.
A: I agree with your diagnosis. The leaf-footed bug is a pest of almonds, pecans, pomegranates, and citrus, among others. They damage the fruit by feeding on it with their piercing-sucking mouthparts. While we may see them feeding, often what we find are the results after the fruit shows signs of rot from the feeding site. There are synthetic insecticides such as Sevin that can be used or if you prefer an organic solution there are pyrethroids such as PyGanic that are OMRI registered products that offer the same result. In either case, it is important to target the insects with the spray since they are contact poisons. The young bugs are the most susceptible and the easiest to target so it is a good idea to monitor your plants every week or so in the spring.
