Recently, an organic grower with a variety of squash crops under low tunnels called Ag Agent Meredith Melendez about wilting plant symptoms.
|Squash Vine Borer Injury|
"Standard" IPM Thresholds Fail
The USDA NOP Standard does not permit organic farmers to make prophylactic (preventative) insecticide treatments, even of OMRI approved insecticides.
Under Early Organic Squash Cultivation
|Squash Vine Borer Adult Moth (R. Bessin)|
That this threshold seems way too high is an agreed upon observation by local grower experiences and the Rutgers IPM team. Organic cucurbit growers who wait to see SVB wilting injury and root feeding evidence before treating risk losing their crops – especially under low tunnels.
While it is too late for saving squash crops this year, Kris Holmstrom of the Rutgers IPM program recommends that an appropriate organic IPM action threshold is catching a single (1) adult moth in a SVB pheromone lure trap placed near the squash field. One or more adults in the trap represent a valid organic threshold-based application, not a prophylactic treatment.
Treatments directed to the base of plants should commence within one week of this first appearance, and probably continue on a weekly basis as long as adults continue to be caught during the early crop. SVB may not be as big a threat later in the season with more host crops available. Kris says, “I would play it on the conservative side with this SVB pest since it hits small plantings so hard, and organic growers have little in the arsenal.”