Cabbage looper Reference Page
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Loopers in Mint Reference Page
Mint—Cabbage and Alfalfa Loopers
Pest common and scientific names: Cabbage Looper (Trichoplusia ni ), Alfalfa Looper (autographa californica) ID photos:
fact page
(pdf):
Pest description and crop damage Larvae are pale green with white lines on backs and sides. They move in a looping manner. Moths are gray-brown with a silvery oval and a U-shape spot on forewings. Early season damage (May, early June) in the Willamette Valley, although appearing serious, most always is outgrown by plants at harvest. This generation usually is parasitized heavily, greatly reducing potential for late season damage from this pest.
Scouting and thresholds Inspect fields in June and early July when scouting for the more serious pests, variegated cutworm and bertha armyworm. Count loopers the same as these pests when doing ground searches for larvae and tallying numbers per ft2. Treatment levels vary depending on vigor/age of field and price of oil, usually from 1 to 4 larvae per ft 2. See Oregon State University publication PNW 182, A Guide to Peppermint Insect and Mite Identification and Management, for discussion.
Management—biological control
This insect easily is controlled
with Bacillus thuringiensis formulations when larvae are small and
leaf coverage complete.
Parasitic wasps and flies usually
minimize summer generation damage by killing larvae in May and June. Look
for small black blotches on otherwise pale green and white larvae of loopers,
as these usually indicate parasitization.
Management—cultural control
Larval feeding damage in May
and June, particularly in western OR, usually is confined to those leaves
which appear on the first regrowth nodes in the spring. The great majority
of these leaves will shade out and fall well before harvest. So, spraying
an insecticide specifically for loopers is uneconomical and possibly reduces
potential for biological control by killing looper parasites active at that
time.
Management—chemical control
1. acephate (Orthene) at 1 lb
ai/a. PHI 14 days. Do not apply more than twice per season. Alfalfa looper
and cutworms only.
2. methomyl (Lannate) at 0.9
lb ai/a. PHI 14 days. Apply in at least 10 gal water/a. Lannate is labelled
for loopers and variegated cutworm.
Warning: These materials are toxic to bees. Do not use during bloom.
Source: 2003 PNW Insect Management Handbook
Integrated Pest Management Information:
OSU Looper Management Publication
U of I Insect Control Recomendations for Mint Production in Idaho; CIS 773
Updated June 17, 2003-jn