Ask the Master Gardener: How to handle pests on squash and zucchini plants

Q: I have had problems trying to raise zucchini in the past, seems that bugs and other problems pop up before I have anything from my plants at all. Is there something I should be doing to have better results?

Without knowing the specific problems you have been having with your summer squash, the most common problems would be squash bugs and squash vine borers. There are both organic and non-organic methods that will help control these issues.

The hardest squash pest to deal with would be the squash vine borer because they are "undercover pests," doing their damage out of sight, not being obvious until the plant is almost gone. After eggs have been laid by the moth and have hatched, the larva will burrow into the stem and eat its way up. The borer can take a zucchini plant down in a couple of days. Look at the base of the plant stem for a hole with "frass" coming out. Some have luck using pyrethrin powder at the base, however this will kill other insects, so might be a last resort. Bacillus thuringeiensis (Bt) is an organic, naturally occurring bacteria that will kill the larva if a liquid form is injected into the stem. Other methods of control include physical barriers such as a foil collar around the stem or floating row covers, succession planting, or planting late in the season. The squash vine borer moth (a species of seslid moth) stops laying eggs in late summer, so many have had success planting zucchini in mid to late July.

Squash bugs are much easier to detect, perhaps a bit easier to control and/or eliminate. They like to hide, so keeping mulch pulled away from around the plant may help. Keep looking under the leaves for eggs, clusters of coppery dots, and scrape off the eggs as soon as possible, also hand picking any adults or nymphs you may find. Other controls to be considered are using a homemade soap spray or coffee ground spray. Neem oil can be effective but also may harm beneficial insects in your garden. Stronger chemical pesticides could be used in extreme cases, however should be the last resort since they also harm all insects.

The soil in my yard is really poor, haven't had much luck with the flowers I have tried in the past. Short of completely amending the soil in my beds, I don't know that to do. What are some plants that will thrive under these conditions?

Many plants will tolerate poor soil, but the ones that are most tolerant of heavy clay soil will be the Missouri native plants found in similar conditions. They have already adapted to the environment and soil conditions, plus have the additional benefit of attracting various pollinators. Some of the best ones include bee balm, blue star (amsonia), butterfly weed (not butterfly bush), common yarrow, Michigan lily, false indigo, goldenrod, purple coneflower, New England aster, and slender mountain mint. Cultivars of these will also work, however pollinators prefer the native versions.

Readers can pose questions or get more information by calling 417-874-2963 and talking to one of the trained volunteers staffing the Mas-ter Gardener Hotline at the University of Missouri Exten-sion Center in Greene County located inside the Botanical Center, 2400 S. Scenic Ave., Springfield, MO 65807.

This article originally appeared on Springfield News-Leader: Ask the Master Gardener: Advice for handling squash bugs and poor soil