Question: I would like to ask for your help with an ID on this insect, since my resources do not show a good match. My bok choy plants are 4 to 5 inches in height, and small holes on plant leaves started showing over the past several day and now cover most starts. The insect is black, flies, and has a “golden” light reflection bouncing off its topside.
Answer: The insects are called flea beetles for their habit of jumping about using their back legs. There are multiple species, and some are common pests in vegetable gardens and some feed on ornamental plants. Adults chew small holes in the leaves that after feeding give the appearance of the leaves being hit with buckshot. Their lifecycle takes about six or seven weeks, so they can have multiple generations each year. In the offseason, they live on other plants such as weeds or discarded vegetable material from the previous crop.
Keeping the area free of weeds and removing or composting old vegetables can help reduce the population. Using row covers, especially when the plants are young, will shield them from the beetles somewhat. Diatomaceous earth may be sprinkled on the plants to help manage them.
Question: I have one grapefruit tree and one lemon tree age 25 years and one orange tree aged 6 years. Since the freeze of 2013, I have covered the trees at each and every frost. In 2014, the grapefruit yield was about 120, the lemons only 10 or 12 and the orange zero. In 2015, the grapefruit was greater, about 150, the lemon 100 and the orange three. In 2016, the grapefruit yield was 150, the lemon 150-200 (large sized) and the orange seven. This fall, the yield looks poor; grapefruit 25, lemon 100 (small) and no oranges. The trees are healthy, with good new growth. I water and fertilize regularly. Why the low yield? Also, when is the best time to prune the trees?
Answer: From your description, everything should be fine, so I am interested to know your irrigation and fertilization schedule and amounts in case they might be tweaked to help improve performance. The recommendation for watering is every seven to 10 days in the summer to a depth of 36 inches. In the spring and fall, watering should be done every 10 to 14 days and in the winter, every 14 to 21 days. Fertilization is recommended three times per year. The amount of fertilizer is based on the tree size and age, and the timing varies slightly based on the type of citrus. I recommend the publication that describes this because a graph is sometimes worth 1,000 words and I don’t have that much space. Google AZ1671 “Citrus Fertilization Chart for Arizona.” In the latest analysis, the oranges and grapefruits are fertilized on a different schedule from the lemons and limes, as you will see from the publication. In general, pruning is something that isn’t recommended for citrus trees unless there are dead, damaged or structurally unsound branches. In those cases, you can prune anytime the saw is sharp.
Question: My tree is in need of a professional trimming. I wonder if you could recommend an arborist or company that could do this. It is a wonderful tree.
Answer: I can’t recommend one company over another because I am supposed to be unbiased. You might want to check with friends and neighbors to see if they can recommend someone they used previously with good results. What I can do is recommend you seek someone that is certified by the International Society of Arboriculture for tree work.
This organization requires a certain amount of training and passing an exam to be certified. They have a place on their website where you can search for arborists in your area by zip code. The web site is: www.isa-arbor.com/findanarborist/arboristsearch.aspx
Question: I have a bougainvillea that’s been growing in my big south-facing window for 45 years. Occasionally, it gets aphids and more recently red spider mites.
Though I have used a systemic on occasion, my usual solution to pests has been to get rid of all the leaves and prune back the spindly limbs so they have nothing to eat. I’ve done this twice in the past six months, but the spider mites seem to persist. The nursery lady told me that root systemic poisons do not work on spider mites, but recommended Bayer Advanced Insect, Disease and Mite Control, which I applied as soon as the plant began to leaf out again. Although I have yet to see a mite, I see the little webs, so I know they’re lurking. Any thought on how to get rid of these guys?
Answer: Mites are microscopic and especially hard to see when they are young. You can manually wipe off the webbing, and that will help reduce the population. Natural enemies may keep spider mites in check to some extent, and so it is sometimes a bad idea to use broad-spectrum products that kill all insects and mites. It is better to use something labeled specifically as a miticide. Mites may also be managed a bit with water. They do best in very dry conditions and simply spraying the leaves with a hose periodically can help reduce their numbers. Be careful not to overdo the water, since bougainvilleas don’t respond well to overwatering.
Keeping the plants in good health is important, and removing all the leaves is contrary to that idea. The mites might also feed on the spindly limbs. Don’t overdo the fertilizer as it makes the plants more attractive to the mites.
