How to Manage Pests
UC Pest Management Guidelines
Mint Root Borer
Scientific name: Fumibotys fumalis
(Reviewed 8/12, updated 8/12)
In this Guideline:
DESCRIPTION OF THE PEST
Wings are cream colored at the base and a mixture of rust-orange
and dark brownish-gray toward the wing tip. Wings are also marked with dark
lines. The wingspan is approximately 0.8 in (20 mm). Males and females appear
nearly identical, although the front wings of females have slightly more orange
Eggs are laid along
the veins on either side of leaves. They are oval, flat, and transparent to
white and turn greenish-brown prior to hatching. Depending on the temperature,
eggs hatch in approximately 5 to 10 days.
Larvae feed on
leaves for 2 to 4 days then drop to the soil surface and burrow into a rhizome.
Mature larvae are white or tan with a reddish-brown head and are about half an
inch long. In October, larvae leave the rhizomes to overwinter in
hibernacula just below the surface (4/5 to 1 5/8 below). Larvae pupate in
Adult mint root
borers start emerging between early and mid-June, with peak emergence occurring
from mid to late July. Mint root borers have one generation per year.
Larvae bore into and feed on rhizomes of peppermint. Economic loss
is due to decreased oil yield, reduced quality of oil, and shorter productive
expectancy of mint stands.
can be released through irrigation at 2 billion infective juveniles per acre.
Tillage can be
effective in late fall or spring when the mint root borer is overwintering or
before adults emerge in June. Rotation with a non-host crop is also a
Monitoring and Treatment Decisions
Sample for mint
root borer larvae from September through October.
Take at least
two, 1 ft2 x 3 inches deep, soil samples for every 2- to 3-acre area
(minimum of 25 samples per field).
roots, and rhizomes, and record the number of larvae found. In addition, roots
and rhizomes can be placed in a Berlese funnel for
approximately 24 hours or until dry to extract larvae.
postharvest treatment if two or more larvae are found per sample.
|The following are ranked with the pesticides having the greatest IPM value listed first—the most effective and least harmful to natural enemies, honey bees, and the environment are at the top of the table. When choosing a pesticide, consider information relating to air and water quality, resistance management, and the pesticide's properties and application timing. Not all registered pesticides are listed. Always read the label of the product being used.
||3.5-5.0 fl oz
||MODE OF ACTION GROUP NUMBER1: 28
||2 lb a.i.
OF ACTION GROUP NUMBER1: 1B
||COMMENTS: Apply postharvest when field
counts indicate damaging levels are present. If ground applied, incorporate
insecticide into the soil with approximately one inch of overhead irrigation
water immediately after application or apply by chemigation.
Make only 1 application of Lorsban 75WG or other
product containing chlorpyrifos during the growing season.
||3 lb a.i.
OF ACTION GROUP NUMBER1: 1B
||COMMENTS: Broadcast and incorporate to a depth
of approximately two to four inches via mechanical means, or immediately
incorporate insecticide into the soil with approximately one inch of overhead
irrigation water. The 48 hour REI is increased to 72 hours in areas where
average rainfall is less han 25 inches a year. Make only 1 application per growing season.
UC IPM Pest Management Guidelines:
UC ANR Publication
Insects and Mites
K. E. Tollerup, Entomology, UC Davis
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