Helen Vanella, Master Gardeners of Greene County
| Special to the News-Leader
Is it too late to plant tomato and pepper plants?
No, it is not too late for these plants to produce a good crop, since we are only a few weeks past the usual planting time. Many plant by Mother’s Day, but plants put in later usually do quite well because the soil and air temperature is warmer so that those later plants quickly catch up with those planted earlier. Some of the tomatoes and peppers that were put in early, even as early as late April, may have experienced cooler temperatures which may have stunted their growth to a certain degree.
Some of my perennials have aphids and I worry that they will take over everything. I have also noticed ladybug larvae on the plants and bees around the area. Is there anything I can use to kill the aphids that will not harm the ladybug larvae or bees?
There is no product that will only kill one particular pest, such as aphids, without harming the beneficials. Since you already have ladybug larvae in place, those wonderful garden helpers will help solve your problem. Other beneficial predators, such as lacewing larvae, parasitic wasps, and praying mantis, will soon arrive to also consume the aphids or any other pests. Nature can strike a balance if we allow things to follow a natural course.
My oak tree has some galls on it. Will this kill my tree? Is there anything I can use to treat this?
In general, oak galls don’t usually kill the tree, unless the infestation is extremely heavy, but they are unsightly and messy. There are more than 1,500 species of galls which are on a multitude of plants, mostly formed by insects and mites, but the most commonly found on pin oaks are the gouty type gall. These mostly affect twigs and smaller limbs, sometimes causing die back with the affected parts breaking off. The best control for these smaller areas would be to prune those off and burn the trimmings.
Heavier infestations can be treated by an arborist with chemicals, however this is NOT a recommended course of action, since systemic chemicals will kill all insects on the trees, including beneficials and also may affect birds who eat those insects. Oak trees are host to at least 500 beneficial insects and caterpillars, as well as the birds who eat them, so can have a very negative environmental impact. I recommend watchful waiting and pruning (and burning) any damaged twigs/limbs.
Cutworms are snipping off my cabbage and broccoli plants. What can I do to eliminate this problem?
One of the easiest and least harmful ways to prevent this problem is to form a barrier around the stems with plant collars made of cardboard, aluminum foil, or plastic, which keeps the cutworms unable to chew into the stem. An insecticide such as a synthetic pyrethroid could also be used. Another possibility would be using Bt (Bacillus thuringiensis), which is also effective in killing the cutworms.
Readers can pose questions or get more information by calling 417-874-2963 and talking to one of the trained volunteers staffing the Master Gardener Hotline at the University of Missouri Extension Center in Greene County located inside the Botanical Center, 2400 S. Scenic Ave., Springfield, MO 65807.