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INSECT AND MITE PESTS


San Jose Scale

San Jose Scale (SJS) can be an extremely important indirect pest of apples. Additionally, under very high population pressure, SJS will also show up on the fruit.

There are two main problems with control of this insect: 1) the insect is very small and so goes unnoticed until large populations have built up; and 2) the insect spends much of its life cycle under a protective cover or scale. Therefore, TIMING of insecticide applications becomes of paramount importance.


San Jose Scale


The adults are very small and the female does not fly. Males will emerge about mid-May and seek out females. Mating occurs and then, about early to mid June, live young (called crawlers) are born. These tiny yellow insects move over the tree in a seemingly random pattern until they locate a suitable site. Once located, the crawler sticks its mouthparts into the tree and secretes a waxy shell over its body. From this point on, female scales will not move. Males will remain in one location until maturity at which time, they will seek out females and begin the cycle again.

SCOUT: Scale, if sampled, will be monitored by 2 methods (1) adult traps will be monitored for about two months in early spring. (2) Known scale infestations will be watched for appearance of the crawler stage. Crawlers can be easily detected by wrapping a small amount of black electrical tape with the sticky side out around a branch. Report the date crawlers are first seen.

ACTION THRESHOLD: Any scale calls for an application during crawler movement. See appendices for pheromone trapping and degree day modeling information.



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