DAMAGE BY TWO-SPOTTED SPIDER MITE (TETRANYCHUS URTICAE) IN APPLE AND COTTON

Аннотация

Tetranychus urticae, the two-spotted spider mite (TSSM), is a highly polyphagous herbivore that inflicts severe feeding damage on many crops, including apple orchards and cotton fields. Its rapid reproduction (a single female can lay >100 eggs and complete a generation in under 10 days) and propensity to thrive under hot, dry conditions lead to explosive population growth. In apples, infestations cause leaf stippling, chlorosis and bronzing, premature defoliation, and reduced fruit set. In cotton, TSSM outbreaks – especially under drought stress or following broad-spectrum insecticide use – produce similar symptoms (leaf spotting, webbing, leaf drop) and can devastate yields. Economically, damage and management of TSSM are enormous: losses can reach thousands of bales in cotton (e.g. >30,000 bales U.S. in 1999) and cost growers on the order of \$4,500 per hectare in affected crops.