ABSTRACT
Root-lesion nematodes (primarily Pratylenchus penetrans) were monitored in two marigold cultivars (Tagetes tenuifolia cv. Nemakill and cv. Nemanon), annual ryegrass (Lolium multiflorum cv. Lemtal), red clover (Trifolium pratense cv. Florex), and soybean (Glycine max cv. Proteus), and in the following potato (Solanum tuberosum cv. Superior) crop during three growth sequences. Meadow fescue (Festuca elatior cv. Miner) and bee plant (Phacelia tanacetifolia cv. Gipha) were added to the trial in the second year. Black-eyed Susan (Rudbeckia hirta, unidentified cv.) and two additional marigold cultivars (T. patula ssp. nana, unidentified cv., and T. erecta cv. Crackerjack) were included in the final sequence. Population levels of root-lesion nematodes were consistently lower under marigolds compared to the other cover crops tested. Correspondingly, average potato tuber yields were significantly higher (8-14%) when potato followed marigolds. The highest levels of root-lesion nematodes occurred under red clover and soybean, and the average potato tuber yields were lowest following these crops.
ABSTRACT
The impacts of fosthiazate on potato (Solanum tuberosum) tuber yields and populations of root lesion nematodes (primarily Pratylenchus penetrans) were studied during 1991-1994 in experimental plots on Prince Edward Island. Tuber yields were greater in treated plots when compared to untreated plots by 8% and 30% during 1991 and 1993, respectively. Numbers of nematodes in roots were reduced by the treatments in every year, and nematode populations in soil were suppressed in 1991, 1993, and 1994. Tuber yields in 1993 and 1994 were higher, and nematode counts in soil and roots in 1991, 1993, and 1994 were lower in plots treated with the emulsifiable concentrate formulations of fosthiazate than in plots treated with the granular formulations. Yields of plots treated with fosthiazate did not differ consistently from yields of plots treated with aldicarb. The results indicated that fosthiazate should be useful for potato production in the Maritime region of Canada.
