2 Cucurbit Crop Studies That Offer Production Guidance
June 27, 2022 Two U.S. research projects take a look at different methods for managing common control problems in cucurbit crops.
Check out the details of these studies that take on different crop protection angles of this topic.
Do Breathable Row Covers and Mulch Protect Against Insects?
The research team, primarily from the University of Kentucky, tested using breathable row covers on crops against the more typical floating row covers. They measured results over two years on long-season crops. The team also tested ground cover treatments — straw mulch and bare ground — for their impact on pest insect levels and yield. They used both squash and melons as the test crops.
Typical row covers are made from spunbonded polypropylene fabric. They’re effective in protecting transplants but are removed to allow bees access to flowers and to prevent high temperatures from killing the crops.
Another disadvantage of the cloth covering is its single use.
The team tested a more durable and breathable alternative of nylon mesh, using it both before and after allowing pollinator access to the crops. Going into the study, they saw many advantages.
- It can be used for several years.
- Growers can scout for pests without needing to lift the covering.
- They’re permeable to insecticide and fungicide sprays.
- They do not cause elevated temperatures underneath.
- They could sharply reduce insecticide exposure to the environment and farm labor alike.
How did it work out?
“Melon yield was always significantly higher in plots with mesh row covers and mulch ground cover. This trend was not observed with squash in 2014 but was true in 2015. In 2015, most plants under the fabric row covers died because of high temperatures immediately after transplanting, highlighting the need for breathable mesh row covers,” the peer-review journal report notes.
The mesh covering effectively reduced both striped cucumber beetles and aphids. Spotted cucumber beetle numbers were so low, the team could not conclude the method was effective for the pest.
As for the straw mulch, the team found combining straw mulch with the mesh cover had the strongest impact on marketable melon yield.
Due to the higher cost of using any covering to pesticide application, the team sees this method being adopted by organic growers in high insect pressure areas.
Study: Effect of Breathable Row Covers and Ground Cover on Pest Insect Levels and Cucurbit Yield, 2022
Authors: Kacie J. Athey, Julie A. Peterson, Jamin Dreyer, James D. Harwood, Mark A. Williams
Timing Is Critical in Fungicide Application for Downy Mildew in Cucurbits
A research team from North Carolina State University and Clemson University examined the timing of how downy mildew progresses and how well various fungicide treatments work. The study took place over three seasons in North Carolina (from 2018 spring and 2019 and 2020 fall seasons) and two seasons in South Carolina (2018 and 2020 fall seasons).
The first visual onset took place in mid-June for spring season crops and mid-September for fall crops.
Here are a few insights learned from the study that growers can use:
Cymoxanil (Curzate) was less effective than fluopicolide (Presidio) or propamocarb (Previcur Flex) and should not be used on cucurbits to manage downy mildew. Cymoxanil was less effective against both the cucumber strain and the squash strain of downy mildew.
Weather conditions, moisture (rainfall and dew periods), and air temperature affect how fast downy mildew develops and how severe it becomes.
Because downy mildew develops quickly when weather conditions are favorable, a weekly spray schedule is critical. (Note: most fungicide labels now say to “apply no more than every seven days,” when in the past, five-day intervals were allowed.)
Applications of effective fungicides slow disease progression (development of downy mildew). This was verified with epidemiological models.
Cucumber had more severe downy mildew than squash (this is not new info).
Authors: Isaack Kikway, Anthony P. Keinath, Peter S. Ojiambo
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