Pests And Pollinators Row Cover

Controlling Squash Pests, Encouraging

Pollinators: Langston University Extension Research

NATIVE TO THE AMERICAS, THE SQUASH FAMILY INCLUDES BOTH SUMMER VARIETIES,

SUCH AS ZUCCHINI AND YELLOW SQUASH, AND WINTER VARIETIES, SUCH AS BUTTERNUT

AND SPAGHETTI SQUASHES, PUMPKINS, AND GOURDS. SOFT-SKINNED SUMMER SQUASH

TYPICALLY MATURE IN A MATTER OF WEEKS, WHILE THE HARDER-SKINNED WINTER

VARIETIES DEVELOP MORE SLOWLY AND CAN BE STORED FOR SEVERAL MONTHS AFTER

AUTUMN HARVEST.

Given these diverse characteristics, squash varieties reducing the quantity of fruit produced and the farmer’s can be planted and harvested six months of the year. potential income. The second risk is somewhat more ‘indiSo it’s no wonder that many Oklahoma farmers culrect.’ When insecticides are used to control pests, pollinators tivate the popular vegetable to supply local farmers can also be killed. The outcome is the same — less fruit and markets and food processing plants — and to genlower income for the farmer.” erate significant income. The squash bug provides a good illustration of the pest There are, however, problems that affect squash crops problem. The bug overwinters as an adult; then, in early and impact the producers, and School of Agriculture and spring, it flies into newly planted crops to feed and to lay Applied Sciences (SAAS) horticulturalist Dr. Tracey Payton eggs on the underside of the plant’s leaves, hidden from is at work solving one of the most significant. Her research, casual view. Often, infestation is only discovered on close funded by an Oklahoma Department of Agriculture inspection, when the farmer lifts a leaf and reveals masses Specialty Crop Block Grant of eggs or hatched nymphs, by and a Sustainable Agriculture which time it may be too late. Research and Education grant While eggs and nymphs are in cooperation with Oklahoma developing unseen, the adults State University, focuses on have been feeding by sucking addressing two important risk sap from the plants, damaging factors involving two quite difvines and reducing their ability ferent groups of insects — pests to produce fruit. Several insecand pollinators. ticides are approved to combat “The first risk,” Payton explained, “is that insect pests, particularly the squash bug and squash vine borer, can cause substantial, direct damage to squash plants, Jim Shrefler, OSU Extension Area Horticulture Specialist, and Dr. Tracey Payton, LU Horticulturalist, plan the placement of row covers on the test plot. Shrefler secured the research grant and has been doing squash bug/row cover research for many years. the squash bug, but adults are difficult to control, and application timing is critical. If timing is off, the crucial pollinators can be harmed. Once plants begin (continues on page 36)

Typically, squash bug eggs are found on the undersides of squash leaves. The eggs are small and hard, resembling strawberry seeds.

The farmer must carefully weigh the potential for crop damage caused by the insect pest against the danger the insecticide poses to pollinating insects.

Eric McHenry, SAAS horticulture technician, and Isaiah Gordon, student researcher, bend hoops used to put row covers in place.

flowering, the farmer must carefully weigh the potential for crop damage caused by the insect pest against the danger the insecticide poses to pollinating insects, which are necessary for fruit set.

EXPERIMENTAL TREATMENTS

Building on prior trials of row covers to keep insect pests away from summer squash plants, Payton’s research investigates ways to exclude the pests while allowing pollinating insects to reach the squash flowers safely. In one test to assess differences in fruit set, row covers were removed at one, two, three, or four weeks after the plants began to flower. Although analysis of data is ongoing, initial indications are that removing the covers in weeks three and four results in an optimal balance between pest control and successful pollination. When covers are removed at one or two weeks, squash bug infestations occur at a typical rate. When they are removed at three or four weeks, infestations decline, pollinators are able to fertilize the flowers, and fruit is soon ready for harvest. An added benefit of using the covers was that plants had more time to develop and mature before pollination and were better able to withstand insect damage.

A second treatment tested different types of row cover — a light frost blanket, a heavy frost blanket, and an open

“Giving farmers options to produce in response to changes in price and demand is an important part of Langston University’s approach to working with smallholder farmers.” — D R . T R A C E Y

PAYTON, LANGSTON UNIVERSITY HORTICULTURALIST

Research plot testing different types of row cover materials.

weave netting — as well as the timing of their removal and replacement over the course of the day. The most promising result, regardless of cover type, was removing the row cover for two hours from 8 to 10 a.m.

BRINGING VALUE TO SQUASH FARMERS

“Results of this research show that farmers can use row covers in an integrated fashion to exclude pests and better manage fruit development — without using insecticides,” Payton said. “In the end, they can earn more money and bring safer produce to market.” In the course of these experiments, Payton also discovered an unanticipated benefit. Farmers can grow plants under covers well beyond the flowering stage, uncovering them for pollinators to access roughly 10 days before the grower needs squash to sell. At present, Payton continues to analyze harvest data and plan further trials. Nonetheless, she expects that, when her findings are disseminated, farmers will be able to exert more control over the production cycle, uncovering multiple groups of plants under different covers to supply produce over a prolonged period or replacing covers to suppress production if there is an oversupply in the marketplace. “Giving farmers options to produce in response to changes in price and demand is an important part of Langston University’s approach to working with smallholder farmers,” she concluded.

For more information, please contact Dr. Tracey Payton, ptracey@ langston.edu.