The Impact of the Leopard Moth Zeuzera pyrina L., (Lepidoptera: Cossidae) Infestation in Casuarina Trees on the Neighboring Pear Orchards in Egypt

Abstract

The impact and relative susceptibility and monitoring of the Leopard moth Zeuzera pyrina L., (Lepidoptera: Cossidae) infestation in pear orchards neighboring and non-neighboring to casuarina trees were evaluated at Borg el-Arab district, Alexandria Governorate , Egypt, during the two successive years 2015 and 2016. The mean rate of Z. pyrina infestation in pear trees neighboring to casuarina trees were 15 – 21% (mean, 18%). However, pear trees far away and not neighboring to casuarina trees showed significantly lower rate of the borer infestation (7 - 9%, mean 8%). On the other hand, the rate of Z. pyrina infestation in casuarina trees neighboring to pear trees 13 – 18% (mean, 15.5%). The degree of Z. pyrina infestation in casuarina trees surrounding pear trees was high (0.42 – 0.57, mean 0.5 moths / tree / year). The degree of infestation in pear trees surrounded by casuarina wind break trees was high (0.55 – 0.77, mean 0.66 moths / tree / year). The degree of infestation in pear trees not-surrounded by casuarina wind break trees was almost half degree (0.28 – 0.37, mean 0.325 moths / tree / year). In all cases, and during the two years of study, moths started to emerge in April and sometimes in May and continued mostly until November sometimes in October. Peaks of moths’ emergency were mostly in August. Summer months showed that, the majority of moths’ activity. Less mean numbers of emerged moths / tree were noticed in spring months, while autumn showed few numbers, and moths stopped emergence during winter months. The seasonal cycle of Z. pyrina moths consisted of 7 – 8 months of moths’ activity in casuarina trees and pear orchards. Generally, infestation in pear orchards rabidly multiplied and increased more than twice at the end of only two years. These rapid increases impose the urgent need of control Z. pyrina in casuarina trees as well as in pear orchards especially when they are surrounded by infested casuarina wind break trees.