Squash bugs are the most serious pest of squash and pumpkins in the garden. They also feed on cucumbers and melons, but are not usually a serious problem.
The adults and nymphs damage plants by sucking plant juices from the stems, buds and fruits. Then, they inject a toxin that causes the leaves to wilt, blacken, and die.
The adults overwinter in garden debris, re-emerge as soon as the weather warms, just as soon as you set out your little squash plants, and mate soon thereafter.
Squash bug adults are easy to identify. They are approximately 5/8-inch long, dark brown or grey, and hard-shelled. They give off a disagreeable odor when crushed. The nymphs are light green and look like little spiders running up the stems of the plants. The eggs are brown to brick red, shiny and hard.
You may first notice small yellow specks on the squash leaves that soon turn brown. Then the leaves will turn brown, dry out and become brittle. Waste no time confronting this pest!
The first line of attack is to kill their eggs before they have a chance to hatch. Squash bugs lay eggs on the undersides of leaves, and sometimes on stems, in masses of a dozen or more in neatly ordered rows. You need to kill the eggs to break their cycle and control the bugs. Get in the habit of scouting your squash plants for the shiny, brown eggs and rubbing them off or crushing them.
Keep your eyes peeled for the small, light green nymphs, which are often present near squash bug
Adult squash bugs can run fast when it is hot, but it's easy to hand-pick them in the cool hours of the day. Drop them into a bucket of soapy water.
The best method for control is prevention through sanitation. Remove old squash plants after harvest, and keep the garden free from rubbish and debris that can provide overwintering sites for squash bugs. Till the area to destroy overwintering sites and to bury the adults.
Crop rotation is also important. Plant your squash and pumpkins in a different part of the garden each year. Praying mantids eat the eggs and nymphs and can be a helpful predator.
Squash bugs tend to develop resistance to insecticides and the adults are difficult to kill. Pyrethrums sprayed on the nymphs and adults is effective as a last resort. Be sure to spray the undersides of the leaves. Neem oil also is effective on the smallest nymphs. Since hatching occurs continually throughout the season, subsequent treatments will be required to assure sufficient control.
Keep your garden clean and healthy and enjoy your squash and pumpkin harvest this year.
Start seeds of broccoli, cabbage, cauliflower and other cool-season crops now. Transplant them to the garden next month and they will be producing for you this fall.
Penstemon are bushy, evergreen perennials that attract hummingbirds with their red, pink, lavender or purple trumpet-shaped flowers all summer and fall.
Roses need water and fertilizer to keep blooming well throughout the summer. Watch for pests and treat immediately to prevent infestations.
Shade-loving begonias will add color and beauty in both planters and hanging baskets.
Fountains create the sound of moving water that is restful and cooling on the patio or in the garden.
ABOUT THE AUTHOR: California Certified Nursery Professional Jenny Watts is co-owner of Sanhedrin Nursery in Willits. Visit www.sanhedrinnursery.com.