Update on aster leafhopper infectivity in Michigan for July 16-20, 2012

Aster yellows infectivity of aster leafhoppers remains high, but leafhopper abundance has dropped.

Aster yellows infectivity of aster leafhoppers continues to be high, but leafhopper abundance in commercial fields in west Michigan has dropped considerably during the past week. Two leafhopper samples were tested during July 16-20, 2012. Please see the map below for the level of aster yellows infectivity and thresholds for treatment.

Thresholds per 100 sweeps:
9% infectivity: celery - 3, carrot - 5
4% infectivity: celery - 9, carrot - 11

To learn more about aster leafhopper biology, trapping and management, see the recent MSU Extension News articles:

Aster leafhopper map
Numbers on map represent percent of leafhoppers infected
with aster yellows. Each number represents a separate sample
collected between July 16-20, 2012.

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