Glena bisulca,1 a Serious Defoliator of Cupressus lusitanica in Colombia2
The cypress, Cupressus lusitanica Miller, was introduced to Colombia over 100 years ago as an ornamental, and in recent decades plantations were established to supply pulpwood and lumber for the Colombian economy. Recently, insect pests have killed trees extensively in some of the plantations. A geometrid, Glena bisulca Rindge, was the insect species responsible for death of many cypress in 1968-69. Through rearings and field observations, many details of the life history of G. bisulca in the Department of Antioquia became known. There were 3 generations per year. In the laboratory, eggs hatched in 11-12 days, feeding took somewhat over 1 month, and the prepupal-pupal period took a little under 1 month. Larvae had either 5 or 6 stadia, generally. More males than females had 5 stadia, but more females than males had 6 stadia. Numerous parasites, predators, and disease organisms were active against G. bisulca. Among these, the fungus Cordyceps sp. and the tachinid Siphoniomyia melas Bigot predominated. However, the cause of population crashes was not discovered. The apparent topographic requirement of drainages and flats for population buildup suggests that, by planting trees unsusceptible to G. bisulca in these situations, outbreaks could be avoided. Clouds and terrain make aerial application of insecticides very dangerous. An attempt was made to use biological control methods. A North American egg parasite of several Geometridae, the scelionid Telenomus alsophilae Viereck, developed in laboratory cultures of G. bisulca eggs, but the emerging adults lived only a few hours. Field releases of T. alsophilae were made as they emerged from North American host eggs; however, the parasite has not been recovered.
Document Type: Research Article
Publication date: February 1, 1972
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Journal of Economic Entomology is published bimonthly in February, April, June, August, October, and December. The journal publishes articles on the economic significance of insects and is divided into the following sections: apiculture & social insects; arthropods in relation to plant disease; forum; insecticide resistance and resistance management; ecotoxicology; biological and microbial control; ecology and behavior; sampling and biostatistics; household and structural insects; medical entomology; molecular entomology; veterinary entomology; forest entomology; horticultural entomology; field and forage crops, and small grains; stored-product; commodity treatment and quarantine entomology; and plant resistance. In addition to research papers, Journal of Economic Entomology publishes Letters to the Editor, interpretive articles in a Forum section, Short Communications, Rapid Communications, and Book Reviews.
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