Ray F. Morris

Enhanced soil microbial degradation of capbofuran and fensulfothion ‐ a factor contributing to the decline in effectiveness of some soil insect control programs in Canada

Abstract Compilation of field efficacy data accumulated over a number of years indicated that cabbage maggot (CM), Delia radicum (L.) control by carbofuran and fensulfothion in Newfoundland has declined with time. A similar trend was apparent in Ontario with carbofuran used to control carrot rust fly (CRF), Psila rosae (F.) and carrot weevil (CW), Listronotus oregonensis (LeConte). Laboratory tests conducted between 1982 and 1985 with 2 Newfoundland CM strains and an Ontario CRF strain indicated that declining efficacy could not be attributed to development of insect resistance to recommended insecticides. Other tests indicated that the 2 Newfoundland soils developed the capacity for rapid degradation of carbofuran or fensulfothion in a single growing season. In an organic soil used for carrot production in Ontario, anti‐carbofuran activity was apparent within 1 wk after application of granular carbofuran in the seed furrow and was high after 3 wk. The data suggest that development in soil of microbial po...

Distribution and Biology of the Golden Nematode, Heterodera Rostochiensis in Newfoundland1)

The golden nematode, Heterodera rostochiensis, was first discovered in Newfoundland in August, 1962. Surveys conducted from 1962 to 1964 showed that this pest was widely distributed in eastern and southern Newfoundland but it was not found in the north or in Labrador. Only three communities were contaminated in the western area of the Province. Infestations were generally confined to small gardens in seventy-eight communities, and very few commercial farms were affected. From 50 to 58 days are required for the golden nematode to complete its life-cycle under Newfoundland soil and climatic conditions. There is only one generation per year. The potato varieties Arran Victory and Urgenta were found to be very tolerant to high nematode populations at Cupids, Newfoundland. In one infested area, seven successive crops of Urgenta potatoes were produced without a single crop failure.