Pupation lasts about a month and adults begin emerging in April. Adults are active from April until early August, with most records from June to July. Both adults and larvae exude an orange, presumably defensive, fluid when disturbed. Little, Ulmus sp. Undoubtedly, the records from plant genera other than Ulmus represent resting or incidental records.
Damage sometimes can be severe.
The leaves are brown and many have dropped. Management Apparently, parasites normally keep populations of M. coryli at non-economic levels. The necessity of the larvae to crawl down the tree to pupate in the soil suggests a vulnerable stage in the life cycle that could be exploited in a control strategy. Insect Management Guide for woody ornamentals Selected References Anderson, D., and C.S. Papp. Blatchley, W.S. 1924.