Establishment and yield of three ryegrasses following aldicarb use, and changes in abundance of plant parasitic nematodes

Abstract

S U M M A R YPure swards of Lolium multiflorum. L. multiflorum var. westerwoldicum and L. perenne sown in August h a d " g r -o n areas treated with either 5 or 10 kn a.i./ha aldicarb than on untreated areas. Total annual drv matter , yields increased by iarger amounts where the greater rate of aldicarb wasapplied; throughout the trial, L. perenne was usually less affected by treatment than iiie other two grasses.Plant-parasitic nematodes were more numerous on untreated than treated plots and were fewest in areas receiving the larger application (except in the second harvest year). Number2 of Tylenchorhynchus and Helicotylenchus were affected most by treatments; abundance of Paratylenchus and Criconemella were little altered.Stem-boring Diptera invaded tillers of all three grasses but infection was least in L. perenne. Invasion occurred only on untreated plots in the establishment year and some yield benefit probably resulted from their control. In subsequent years invasion was similar on treated and untreated areas. Effects on other, non-target organisms were not assessed.Ectoparasitic nematodes multiplied more in L. multiflorum plots than in others during the first full-harvest year. The next year numbers of Paratylenchus only were greater in plots of L. perenne than in other plots.Sward persistence of L. multiflorum var. westerwoldicum was better on treated than untreated areas.It was concluded a) that aldicarb use greatly decreased nematode numbers and yields from treated areas were larger than from those untreated; b) that sward persistence was similarly improved following aldicarb use and c) that ryegrasses differed in their suitability as hosts to ectoparasitic nematodes.

Ryegrass establishment and yield in relation to pesticide treatment, irrigation and fertiliser level

“…Annual yield increases following pesticide application were small in comparison with responses to fertiliser and irrigation. The only invertebrate pests prevalent in significant numbers at the start of the experiment were root-ectoparasitic nematodes and these were less abundant than had been associated with poor ryegrass establishment by Spaull, Mewton & Clements (1985).…”

“…The effect of certain insect pests, especially stem-boring Diptera upon ryegrass yields is well established (Henderson & Clements, 1979;Clements, 1980) and there is evidence that nematode control can improve establishment and yield of ryegrasses (Bezooijen, 1979;Spaull & Mewton, 1984;Spaull, Mewton & Clements, 1985). Certain foliar, fungal diseases may reduce yields of established swards (Carr, 1975) and the effects of soil-borne diseases during establishment are now better understood (Lewis & Lam, 1984).…”

Progress in breeding perennial forage grasses for temperate agriculture

“…By using a range of chlorpyrifos concentrations to control leatherjackets (larvae of Tipula paluidosa) and measuring its effect on DMY, Blackshaw (1984) estimated that they were responsible for annual losses in DMY of 1 t/ha in Northern Ireland (UK). The increases in DMY and persistency of ryegrasses following different levels of aldicarb application indicated significant damage from nematodes (Spaull et al 1985).…”

Betekenis van plantparasitaire nematoden voor Nederlands productiegrasland

“…Bij de vrijlevende ectoparasieten van het geslacht Tylenchorhynchus werd een begindichtheid van 540 nematoden 100 ml -1 grond (in bodemlaag 0-20 cm) geassocieerd met een opbrengstreductie van 18% over een periode van meer dan twee jaar na de herinzaai van grasland (Spaull et al 1985). Voor…”