Many gardeners, too many I think, reach for the sprayer when faced with a pest problem. There are other ways to deal with pests. One way is to pick off pests and squish, drown or smash them. Our opposable thumb, which took three million years of evolution to develop, allows us to do that, so celebrate our thumbs by using them to be greener.

Squash bugs (Anasa tristis) are nasty pests of the cucurbit family; zucchini, cucumbers, squash and pumpkins. Adults (5/8 inch long) are dark brown or gray which keeps them camouflaged around plants. Adults and young nymphs, as they feed, inject a toxic substance that causes host plants to wilt. When feeding is severe, leaves become black and die back. This condition is often referred to as “anasa wilt” which closely resembles bacterial wilt, a true plant disease. They also stink when crushed, so be forewarned that drowning them in a container of soapy water is a good option.

I battled squash bugs for years by picking off overwintering adults and destroying their eggs when they showed up on my zucchini. I often had volunteer squash plants that I used as decoys to attract them and I would destroy the plant and the bugs. I did this for years and I usually lost the battle, but finally they met their Waterloo. I eliminated the overwintering adults before they could reproduce about 6 years ago. Since then, I have been free of squash bugs in my garden. I am fortunate that I don't have close neighbors growing squash as a nearby supply of recruits might have undone my efforts, but I am so glad not to have to deal with this serious pest anymore.

Other pests that we all deal with are slugs and snails. The brown garden snail, Cornu aspersum, is the nemesis of California gardeners. It was introduced from France during the 1850s for use as food. They do provide food for my chickens, but I'll take a pass. I don't know who brought them over, but likely someone with little knowledge of the ecological harm such introductions can do. Such is the case with myriad introductions. Starlings, Japanese beetles, various other insects in the USA and rabbits in Australia come to mind.

There are baits which help control snails and I have used both the metaldehyde bait which is not child or pet friendly and the iron phosphate bait which is safe to use around pets. However, four years ago I decided to remove snails by hand picking and I have been successful in reducing their numbers, but will likely never eliminate them.  I go out early in the morning, sometimes with a flashlight to do my snail hunting. The first year, 2012, I picked off 3,287 and in the following year, 3,747. In 2014, they were much harder to find and I only got 220. This year, I am at 230 and still counting. Since I reduced snail abundance, my iris leaves are unblemished.

About 4 years ago, I was besieged by spotted cucumber beetles(Diabrotica undecimpunctata) which eat bean and cucumber leaves and Dahlia and Gladiolus blossoms. I didn't care much about the leaves—I was willing to share, but Dahlias and Glads are another story. Ruining flowers was not tolerated, so I started crushing them on the bean leaves (they are a little slow on take-off) and after killing 450 the population was severely reduced to a minor nuisance. This beetle shows up in abundance in some years and in others it is barely present. What makes insects so very abundant in one year and barely present in another? This conundrum can drive scientists to distraction.

This year we had a much warmer than average spring and there were few aphids on rose buds. It could be cause and effect, but it could have been other factors. Complex environmental factors can affect different life stages of populations. As gardeners we can be glad the aphids were not abundant on our roses, but last summer I had problems with aphids on cucumbers, zucchini and melons. The IPM website, http://www.ipm.ucdavis.edu/PMG/r116300711.html, lists information on cotton aphids (Aphis gossypii) that attack melons.

Unlike rose aphids, the cotton aphid thrives in hot weather. It can vector cucumber, zucchini yellow, and watermelon mosaic viruses, among others. These virus diseases may be more destructive than direct aphid feeding. Host weeds for this aphid include milkweed, jimsonweed, pigweeds, plantain, and field bindweed, so keeping these host weeds controlled may be helpful. If cotton aphids, which are difficult to control, will just not show up this year on my melons, cucumbers and zucchini, I will be one very happy gardener!

If you have a gardening related question you can contact the UC Master Gardeners at 209-953-6112. More information can be found on our website.