LBAM Finds Require Grower Response

The Light Brown Apple Moth (LBAM) is an invasive exotic leafroller that feeds on a wide range of host crops in California. This year, it seems that heavy spring rains kept growers on the Central Coast from taking usual steps to control LBAM and, as a result, many LBAM larvae have hatched and higher than normal numbers of LBAM have been found, particularly in strawberries.

LBAM Quarantines

Although it does not pose a major threat to most crops, the state of California has gone to great lengths to prevent accidental shipment of LBAM to areas where it isn’t established. Places where LBAM has been found are under a quarantine against the pest. The quarantine applies to many (but not all) of LBAM’s host crops.

Twenty-two counties in California are under quarantine for LBAM. The quarantine means that shipments of affected crops outside of the quarantine area must be inspected and verified free of LBAM larvae before being shipped. For information about quarantine boundaries and requirements, visit the LBAM Program Website.

Managing LBAM on Your Farm

Organic growers need to take steps to reduce LBAM populations. University of California Cooperative Extension Farm Advisor and Director for Santa Cruz County Mark Bolda offered management suggestions and scouting information in two recent blog entries.

1.  Regularly scout fields for presence of LBAM. Bolda posted pictures online of larvae, pupae, and leafrolling and webbing signs of LBAM in the field.
2.  Physically remove any rolled leaves and kill the larvae inside.
3.  Spray to kill the larvae. Entrust is effective at managing these leafrolling pests, but can only be applied three times in a season (twice for caneberries), while Bt is generally not as effective against LBAM. Bolda recommends planning to space Entrust applications over the season,  supplemented with a program of regular Bt sprays, preferably in the evening because UV radiation can break down Bt.
4.  Install mating-disruption twist ties throughout your fields now. These twist ties emit a pheromone that confuses LBAM and interferes with its mating activity, thereby decreasing future population size, but it does not control or kill existing larvae or moths. Another moth flight will occur imminently, so get the twist ties out now to reduce LBAM pressure later.
5. According to Bolda, twist ties must be spread out evenly over the field, not bunched up in one area. He also suggests raising them on flags, lines, or sticks above the canopy and suggests placing them every 10-15 feet every third bed, for a total of 300 ties per acre.

Make Sure Materials Are Compliant
CCOF-certified berry growers may have pheromone twist ties listed on their Organic System Plan, but if you don’t, or you intend to use a different product than you have in the past, make sure to add the material to your OSP. When in doubt about whether or not a material can be used in certified organic production, contact your certification service specialist. If you don’t know who your certification service specialist is, call the CCOF office at 831-423-2263 and they will forward your call to the appropriate person.

Mark Bolda is available to speak to growers in Santa Cruz county and can refer callers to specialists in their county. Contact Bolda at (831) 763-8025 or mpbolda@ucanr.edu.

Other LBAM Resources:

• CDFA LBAM pest profile
• USDA APHIS LBAM information