COVID-19 Extension Updates and Resources ... More Information »

Close message window

Give Parthenocarpic Squash a Try Next Year

4 weeks after planting, first harvest. Paul Thompson, ©2021, Clemson Extension

4 weeks after planting, first harvest.
Paul Thompson, ©2021, Clemson Extension

I don’t know about you, but summer squash and cucumbers are a necessity in my garden. Problem is, after a few years, the squash pests show up in greater abundance each year, and only a couple of weeks after harvesting your first squash, the vines are in decline, and production goes to zero in another week or two.

Vine Borer larva and damage. Paul Thompson, ©2021, Clemson Extension

Vine Borer larva and damage.
Paul Thompson, ©2021, Clemson Extension

Vine borers are certain death, and spraying the vines every five to seven days to prevent them is not something I want to do; plus, there are all the bees visiting the flowers that prevent you from spraying during the day – and squash flowers are so large a lot of male solitary bees like squash bees or carpenter bees like to spend the night in them for protection.

Male squash bees. Paul Thompson, ©2021, Clemson Extension

Male squash bees.
Paul Thompson, ©2021, Clemson Extension

Squash bugs overwinter as adults in protected locations and will “smell” the squash with their antennae from long distances away and will arrive to mate and lay eggs within a week or two of planting.

2 weeks after planting squash bug trying to get in. Paul Thompson, ©2021, Clemson Extension

2 weeks after planting squash bug trying to get in.
Paul Thompson, ©2021, Clemson Extension

Later in the summer, the pickleworm moths show up whose caterpillars bore holes in the fruit. Unfortunately, the holes in the fruit are quite small, so you often don’t discover the worms until you slice into it.

Pickleworm hole and frass. Paul Thompson, ©2021, Clemson Extension

Pickleworm hole and frass.
Paul Thompson, ©2021, Clemson Extension

Squash and other cucurbit vegetables such as cucumbers and melons have separate male and female flowers on the same plant, requiring pollinating insects such as bees to transfer the pollen to the female flowers for fertilization and fruit development. Parthenocarpic squash varieties, which are all zucchini types, were developed for greenhouse production. Parthenocarpy means that fruit is produced without the need for pollination.

There are many manufacturers of insect row covers that can be used in lieu of constructing a greenhouse, and these squash perform quite well in the garden and are highly productive, with almost all of the female flowers producing fruit. There are also cucumbers that were developed for the same purpose. So instead of fighting the squash pests with insecticides, give these greenhouse varieties a try. Seeds are available from many online seed companies. I have grown these varieties:

Golden Glory, a yellow squash variety that is shaped like a zucchini (I think it tastes more like a zucchini than a yellow squash, although it isn’t as watery as zucchini).

Nocha, a dark green prolific variety.

Dunja, also dark green with virtually spineless plants.

Cabbage and broccoli under row cover. Paul Thompson, ©2021, Clemson Extension

Cabbage and broccoli under row cover.
Paul Thompson, ©2021, Clemson Extension

As a side note, these row covers are also quite useful for cole crops such as cabbage, broccoli, collards, and kale to keep the cabbage worms away by excluding several moth species and the cabbage white butterfly from laying eggs that hatch into the caterpillars that can devastate those crops.

For more information on squash and row covers, see HGIC 1321, Summer Squash.

If this document didn’t answer your questions, please contact HGIC at hgic@clemson.edu or 1-888-656-9988.

Factsheet Number

Newsletter

Categories

Pin It on Pinterest

Share This