Insects and diseases outlook

The cool damp conditions we are experiencing in 2011 should promote the growth of various diseases that will affect trees, but it should not encourage insect outbreaks, especially in the lepidopterous "moth and butterfly" group (of which gypsy moth is a prominent member).

Gypsy moth numbers saw a steep decline after 2009, and if they behave like historical models, there should be eight to 10 down years following the three up years we experienced in 2007, 2008 and 2009.

There were very few viable egg masses deposited in Frederick County last summer, and gypsy moth egg mass counts are low. As a result, there will not be much gypsy moth presence this spring. Although no counting of Eastern tent caterpillars, forest tent caterpillars or oak span worms are taken, these insects should be on the low side also, based on the weather conditions.

The weekly forest pest alert generated by the University of Maryland Extension Service lists a number of scale insects being found on trees and the presence of the anthracnose fungus already appearing in areas where the trees have leafed out. It looks like diseases will be more of a problem this year than insects ... not counting stink bugs.

Nature Notes for 4/17/2011