Degree Days Soil Temp. New England Ag. TSSM can be especially abundant where row covers were used. So far, TPB have been found in moderate to low numbers in strawberry fields and apple orchards. However, populations may jump suddenly, especially in warm, sunny spells.
Damage is most significant just after petal-fall.
In the past, we used an action threshold for TPB nymphs of an average of 0.25 nymphs per flower cluster or greater than 4 infested clusters out of 30 sampled. The latter threshold allows you to simply note presence or absence of TPB nymphs in a cluster rather than counting them. To save time, a sequential sampling plan may used to determine how many clusters should be sampled. If you find 3 or more TPB nymphs, control is required in order to avoid economic damage to your crop. If the maximum of 50 flower clusters are sampled and no decision is indicated, the grower should sample again in 1 or 2 days.