Researchers and pesticide manufacturers continue to make progress in their attempt to fight citrus leafminers. Two relatively new pheromone-based products— SPLAT CLM and MalEx—help control the pest without affecting non-target species.
It was back in the late 1990s when growers began spraying for Asian citrus psyllids that they inadvertently caused a resurgence of citrus canker.
The broad-scale insecticidal treatments killed off beneficial insects that had kept citrus leafminer more or less in check. That, coupled with weather and other conditions conducive to citrus canker, prompted the disease to once again become a problem.
Citrus leafminer larvae burrow into citrus leaves, creating tunnels or mines. The wounds provide an entryway for citrus canker bacteria to enter.
Leafminer feeding itself can affect yields and stunt growth of trees, particularly young ones and nursery trees, says Lukasz Stelinski, assistant professor of entomology at the University of Florida’s Institute of Food and Agricultural Sciences Research and Education Center at Lake Alford.
Two pheromone-based materials have been developed that specifically target the leafminer—SPLAT CLM, manufactured by Riverside, Calif.-based ISCA Technologies Inc., and MalEx, made by Portland, Ore.- based Alpha Scents Inc.
SPLAT CLM is a mating disruptor, and MalEx is an attract-and-kill material.
The theory behind mating disruption is you flood an area with so much synthetic female pheromone that the male insect becomes confused and can’t find a female with which to mate.
In the case of SPLAT, short for Specialized Pheromone & Lure Technology, the pheromone is contained in a mixture of non-toxic,food-grade waxes and oils that is squirted on tree trunks.
The mixture goes on with the consistency of hand cream that hardens to the consistency of crayons or wax candles in a few hours, according to product literature.
The most exciting news is the recent breakthrough in synthesizing the active ingredients, Stelinski says.
The discovery has knocked down the price from a budget-busting $300 per acre to about $40 per acre, he says.
The lower price “positions it as very affordable for growers, considering the duration and efficacy,” Stelinski says.
SPLAT CLM may now have “significant practical applications for controlling leafminer,” he says.
The manufacturer is marketing SPLAT CLM, and growers are buying it, says Stephen Lapointe, research entomologist at the U.S. Horticultural Research Laboratory in Fort. Pierce.