Integrated pest management in cole crops

Zsofia Szendrei

Professor, Extension Specialist

szendrei@msu.edu

Outline

Damage

Cabbage white a.k.a. imported cabbageworm

‘fuzzy’ caterpillar

Diamondback moth

‘wriggly’ larva

Cabbage looper

‘inchworm’

Diamondback moth

Cabbage white

Using B.t. for caterpillar control

• Application frequency more important than rate
• Every 7 days better than every 14 days
• Daytime spray as effective as evening spray

​

• More effective on young larvae

​

• Thorough spray coverage: lots of water, pressure, surfactant

​

• Does not kill natural enemies of pest

​

• Works best when diamondback moth and cabbage white are the dominant pests, loopers are more difficult to manage

​

Other insecticides for caterpillar control

• Entrust – OMRI certified

​

• Coragen, Besiege – better for natural enemies than pyrethroids, etc.

​

• Pyrethroids are commonly used but diamondback moth resistance is a problem

​

• Apply foliar insecticides at threshold

​

• Verimark tray drench

​

​

​

​

April - July

Aug-Oct

B.t. if diamondback moth or cabbage white are dominant

Confirm, Intrepid, Besiege, SpinTor, Entrust, pyrethroids if cabbage looper dominant

Caterpillar thresholds

Insecticide recommendations

Pest thrips

Beneficial thrips

Thrips damage

Cultural management of thrips on cabbage

• Thrips-tolerant varieties

​

• Winter cover crop selection: avoid wheat, choose rye

​

• Crop rotation: avoid planting near wheat

​

• Trim off damaged areas

​

​

Insecticide program for thrips on cabbage

Sequence of 4 insecticides, each sprayed twice in a row every 10 days:

Lannate

Radiant

Assail

Exirel

Flea beetles

• Trap crops
• Plant earlier than the main crop to draw flea beetles (typically 7-14 days in advance).
• On 10% of the crop area
• Along the field border or along side of field
• Pacific Gold Mustard and Pac Choi draw flea beetles to them

​

• Field sanitation

​

• Crop rotation

​

• Later planting date

​

• Row covers?

​

• Verimark tray drench

​

• Foliar insecticides: use thresholds, young plants need more protection

​

Flea beetle management

Biological control agents

Insectary plants

Sweet alyssum

Strip tillage and cover cropping

Cabbage maggot

Maggots emerge from previous cole crop plantings

3X

• One complete cycle = generation

​

• 3 generations per year

Cabbage maggot lifecycle

Applying insecticides at the base of the plant

Banned: chlorpyrifos (Lorsban) on cole crops

Distribution permitted until April 30, 2025

Appropriate use of existing stocks permitted until

June 30, 2025

How to apply insecticides?

Insecticide for maggots in transplanted cole crops

• Verimark is currently the most effective
• Apply as tray drench
• Controls other common pests (worms, flea beetles)
• Tricky to apply and expensive

​

First generation of maggots can be forecasted

Direct seeded cole crop insecticide options are lacking!

Floating row covers

Best option for direct seeded cole crops for maggot management

Acknowledgements

• Ben Werling – MSU Extension
• Tyler Reisig – MSU Vegetable Entomology
• Celeste Weltey – The Ohio State University
• Christy Hoepting, Brian Nault – Cornell University

QR code for this presentation

Cabbage maggot survey

Caterpillar management with insecticide in cole crops

​