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Baird (A. B.). Some Notes on the Natural Control of the Cherry-tree 

 Ugly Nest Tortricid, Archips cerasivorarm. Fitch. — Agric. Gaz. 

 Canada, Otfaiva, v, no. 8, August 1918, pp. 766-771, 6 figs. 



The large tent-like webs of Tortrix {Archips) cerasivorana, Fitch, 

 are frequently seen during June and July on choke-cherry trees along 

 country roads in Canada. The eggs of this moth are deposited in 

 late July or early August on the bark of small cherry trees, generally 

 near the base, very Uttle development taking place in the embryo 

 imtil the follomng spring. In the egg-stage this moth is parasitised 

 by the Chalcid, Trichogrammatomyia tortricis, Gir., which probably 

 spends 4 or 5 weeks in the host egg, as the adults emerge during the 

 end of August and beginning of September. In 1917 from 75 per cent, 

 to 80 per cent, of the eggs were killed by this parasite. The larvae 

 of T. cerasivorana hatch during late May and early June and crawl 

 to the top of one of the branches, where they congregate in the opening 

 leaves, spin their webs and begin to feed, extending the web to cover 

 fresh food as this is required. As soon as there is sufficient excreta 

 and frass in the nest, the larvae construct among it silk-lined cells in 

 which they live individually. There are six larval instars, most of 

 the larvae being mature by mid- July. Several species of parasites 

 have bee a reared from the larvae, those occurring in Canada including 

 Apanteles sp., several individuals of which issued from yoimg 

 larvae. The Tachinid, Dichaetoneura leucoptera, Johns., infests the 

 larvae of T. cerasivorana during the first three weeks of July. The 

 parasitic larvae moult twice and become full-grown in about 3 weeks, 

 when they eat their wav through the side of their host and either 

 pupate in the nest or fall to the ground and pupate under rubbish. 

 The host larvae may live for some time after the parasites have escaped, 

 but none reach maturity. The adult parasites emerge in 10 to 14 days 

 and live for some considerable time, possibly wintering in this condition. 

 As many as 40 per cent, of the lari'ae have been parasitised by this 

 species. The Hymenopteron, Erigorgus prismaticus, Nort., usually 

 destroys 25 to 30 per cent, of the larvae. Eggs are deposited in the 

 host larvae when about two-thirds grown, and the parasitic larvae 

 grow very slowly until after the host has pupated, when they rapidly 

 devour the tissues and mature in a few days, pupating in the empty 

 pupal skin of the host and emerging in a week or 10 days. They 

 probably winter in the adult stage. The Tachinid, Exorista hoarmiae, 

 Coq. , attacks both the larval and pupal stages, pupating in the empty 

 pupal cases of the Tortricid and issuing as adults in about two weeks. 

 Parasitism by this species was not found in more than 5 per cent, of 

 the individuals examined. Predaceous birds and insects have very 

 little chance of controlhng T. cerasivorana in the larval stage owing 

 to the nature of the nest. Pupation takes place within the cells in 

 the nest, and after about ten days, when the adults are about to 

 emerge, the pupae come out of their cells and attach themselves to 

 the outside of the web. Scambus conquisitor, Say, is the only true 

 pupal parasite, but is responsible for the destruction of less than 

 5 per cent, of the pupae. Many pupae however die, apparently owing 

 to drying up of the pupal case. The adults do not disperse to any 

 distance unless carried by wind. Adverse weather conditions and the 

 work of birds throughout the season, together with parasitism by 

 insects, are generally sufficient to hold this Tortricid in check. 



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