Keith Mickler's column: Squash plant looking squishy

By Keith Mickler

Floyd County Extension Coordinator

 

While out strolling through my vegetable garden (what a mess) I noticed this charming little gorgeous bug. It was very colorful and just flying in and out and around my squash and zucchini plants. As I watch this critter I caught its mysterious ways, it laid an egg on my squash plant. Look out bug, it's on now. You just laid your last egg pal. Needless to say, all that charm and gorgeous gone and I was gone to get my bug killer.

 

If you haven't figured it out yet, this not so charming bug is the ever dreaded squash vine borer which is the number one suspect behind the demise of squash and zucchini plants around the south. This bad little bug has come on quickly due to warmer temperatures the past few days.

 

Squash vine borer is a key pest of squash, gourds and pumpkins in the south. Unfortunately, it is usually noticed only after it has done its damage. Symptoms appear in early to mid-summer (or now) when a long runner or entire plant suddenly wilts. Infested vines usually die beyond the point of attack.

 

Sawdust-like frass (aka-squash vine borer stinky) near the base of the plant is the best evidence activity. Careful examination will uncover yellow-brown pooh pushed out through holes in the side of the stem at the point of wilting. If the stem is split open, one to several borers are usually found.

 

The caterpillars reach a length of 1 inch and have a brown head and a cream-colored body. Unlike most moths, they fly about the plants during the daytime, actually looking more like a wasp than a moth.

 

This insect overwinters as pupa one to two inches below the soil surface. The larva pupates in the spring; with the adult moths begin to emerge about the time the plants begin to run. The crazy critter continues to fly through mid- August. The small brown eggs, laid individually on leaf stalks and vines, hatch in seven to 10 days. The newly hatched larva immediately bores into the stem. The larva will feed for about two to four weeks before exiting the stem to burrow in the soil and pupate. There can be 1 to 3 generations per year.

 

Management

The key to stopping the squash vine borer is controlling the borers before they enter the stem. Once inside the vine, insecticides are frequently ineffective but there is always a slight chance an insecticide might work.

 

You can also use yellow traps to detect squash vine borer adults. This can be any container (pan, cup or bowl) colored yellow and filled with water. Because squash vine borer adults are attracted to yellow, they will fly to the container and be trapped when they fall into the water. Place traps now. Check your traps at least once a day. When you notice squash vine borer adults in your traps you know they are active and it is time to take further action.

 

Use two insecticide applications (such as bifenthrin or esfenvalerate) seven days apart to control hatching larvae. Continue to monitor for additional activity. Sprays need to penetrate into the canopy and down onto the soil to be effective.

 

Some home gardeners have had triumphant victories with deworming the vines. At the first signs of the sawdust-like frass, vines are slit lengthwise near where the damage is found and the borers removed. The stems should be immediately covered with soil. Make sure to burying a few nodes along each vine will encourage rooting at each nodes. This will lessen the impact if squash vine borers girdle the base of the vine.

 

When all else fails and you can stand it no longer, visit your local farmers market for your squash fix, no one has to know you didn't grow'em. I would even place a few of them bought squash out among my dying plants to sooth the anxiety.

 

Keith Mickler is the County Coordinator and agriculture agent for The University of Georgia/Floyd County Cooperative Extension. Located at 12 East 4^th Ave, Rome, GA 30161 (706) 295-6210. Office hours are Monday-Friday 8:00 a.m. - 5:00 p.m. The University of Georgia Cooperative Extension - Learning for Life. Agriculture and Natural Resources, Family and Consumer Sciences, 4-H Youth.  An Equal Opportunity/Affirmative Action Institution. To obtain extension publications please visit our web site www.ugaextension.com or contact your county Cooperative Extension office.