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Infestation
About: Infestation is a research topic. Over the lifetime, 8308 publications have been published within this topic receiving 82305 citations.
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TL;DR: In this paper, the authors evaluated four species of Cruciferae [canola species Brassica rapa L., Brassica napus L., and Brassica juncea (L.) and Sinapis alba L. under field conditions in central Alberta, Canada.
Abstract: Four species of Cruciferae [canola species Brassica rapa L. and Brassica napus L., and mustard species Brassica juncea (L.) and Sinapis alba L.], and various cultivars of each species, were evaluated for susceptibilities to infestation by Delia spp. (Diptera: Anthomyiidae) under field conditions in central Alberta, Canada. Susceptibility was measured throughout the season by recording numbers of eggs of Delia spp. laid on or near individual plants, and at the end of the season by a semi-quantitative determination of injury inflicted by larvae on taproots. Differences in susceptibility occurred among and within canola and mustard species. Plants of B. rapa were most susceptible to Delia spp.; both mean eggs per plant and mean damage ratings per plant on B. rapa significantly exceeded those of all other species studied. Intermediate susceptibility was observed for plants of B. napus and B. juncea; plants of S. alba were least susceptible. In general, differences in susceptibility were greater among species than among cultivars within species. Root damage generally correlated with oviposition among and within species, suggesting that the mechanism of resistance by cruciferous species to infestation by Delia spp. is antixenosis or nonpreference. Results of this study indicate that canola growers in regions infested annually by high population densities of Delia spp. should seed B. napus or B. juncea rather than B. rapa. However, if a short growing season necessitates seeding B. rapa, then growers should select the more resistant cultivars of this species.
64 citations
TL;DR: Hereford cattle kept on a high-quality diet were studied over a treatment period of 11 weeks with the tick-infested animals being infested regularly with equal larval doses for each animal.
Abstract: This experiment was designed to measure the effects of infestation by B. microplus on cattle and to separate the effects of reduced food intake ("anorectic effect") from those due to the remaining factors of tick infestation ("specific effect"). Hereford cattle kept on a high-quality diet were studied over a treatment period of 11 weeks with the tick-infested animals being infested regularly with equal larval doses for each animal.
64 citations
TL;DR: The small intestine of rats was divided into twenty sections in a reproducible manner in order to study the distribution of Nippostrongylus brasiliensis by stretching it under a tension of 5g in adrenaline saline, finding fourth-stage larvae were found chiefly in the sections that were later most heavily parasitized by adult worms.
Abstract: The small intestine of rats was divided into twenty sections in a reproducible manner in order to study the distribution of Nippostrongylus brasiliensis by stretching it under a tension of 5g in adrenaline saline. A small but significant difference between the distribution of parasites in male and female rats was observed. As larvae had virtually ceased to reach the intestine by the fifth day all changes in distribution after that day were due to movements of the established adult population. Up to the twelfth day of a primary infestation the majority of the worms were found between the third and tenth sections, the population mode being in the fifth or sixth section. After the thirteenth day the number of worms in this region fell sharply. The female worms had not ceased from egg-laying by the time most of the worms were being rejected. The posterior half of the small intestine, i.e. the eleventh to twentieth sections, was not heavily parasitized, many of the worms seen being in passage to the anus. The first section was not parasitized until the seventh day, but thereafter remained parasitized until long after worms had disappeared from the more posterior sections. The relative number of male worms present increased as the infestation aged. Throughout the experiment the relative number of male worms present at the anterior end of the smaller intestine was higher than that at the posterior. Fourth-stage larvae were found chiefly in the sections that were later most heavily parasitized by adult worms.
64 citations
TL;DR: Infestation intensity and tissue damage together with field observations strongly indicate that infestation by C. cerastodermae I was responsible for the mass mortality of C. edule during the summer of 1991.
Abstract: The trematode Cercaria cerastadermae I, a parasite of the cockle Cerastaderma edule, is recorded for the first time in Scandinavian waters. More than 20% of the investigated population of C. edule was infested by C. cerastodermae I, and most individuals showed severe tissue damage. Infestation intensity and tissue damage together with field observations strongly indicate that infestation by C. cerastodermae I was responsible for the mass mortality of C. edule during the summer of 1991. Patterns of infestation intensity, damage to the bivalve foot and an experiment on burrowing behaviour suggest that infestation by C. cerastadermae I impairs burrowing ability. The resulting large numbers of C. edule lying on the sediment surface may be misinterpreted as being caused by other factors e.g. oxygen deficiency.
64 citations
TL;DR: The rice brown planthopper, Nilaparvata lugens (Stal), major pest of rice in most of Asia, underwent optimum development at 25 and 29°C, but 33°C was detrimental to all life stages, and tolerance to hopper burn appeared to be the major factor in the differences of susceptibility.
Abstract: The rice brown planthopper, Nilaparvata lugens (Stal), major pest of rice in most of Asia, underwent optimum development at 25 and 29°C, but 33°C was detrimental to all life stages However, this effect was moderated considerably by rearing the insects at 12-hour alternations of 25° and 33°C or 29° and 33°C
While high planthopper populations caused “hopper burn,” lower infestations reduced the number of tillers, number of panicles, and total grain weight of the plants Unfilled grains resulted from infestation during the reproductive reproductive growth stage of plants but not from infestation during the vegetative phase There were distinct differences in the susceptibility of 20 selected varieties to this species While some of these varieties were less preferred by the insect and showed some antibiosis effects, tolerance to hopper burn appeared to be the major factor in the differences of susceptibility There were no apparent correlations between the resistance of these varieties to the brown planthopper and their resistance to the rice green leafhopper
64 citations