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Bionomics of the Poplar Petiolegall Aphid (Homoptera: Pemphigidae) on Crucifer

出版	Texas A & M University, 1991
URL	http://books.google.com.hk/books?id=6eDltgAACAAJ&hl=&source=gbs_api

註釋The biology and ecology of the poplar petiolegall aphid (PPGA), Pemphigus populitransversus Riley was studied relative to commercial cabbage and broccoli production in the Lower Rio Grande Valley of Texas. Cabbage and broccoli fields planted before December were exposed to immigration by fundatrigenia, and as a result, sustained progressively higher population densities of alienicolae (range 21-477 aphids per plant) the earlier they were planted. Between-plant distribution of PPGA density was aggregated, as described by Taylor's Power Law. Sample size estimates for fixed precision levels of 10 and 25% of the true mean ranged from 176-14, depending upon aphid density and precision level. A binomial sampling plan is proposed based upon a non-linear relationship between aphid density and proportion of infested plants that would allow a more rapid estimate of population density. Cabbage and broccoli exhibited injury response from root feeding by alienicolae. Yield potential was reduced 8-60% in unmanaged cabbage plantings compared to managed ones and was manifested through two components; a reduction in cabbage head fresh weight and a net reduction of harvested cabbage heads. Quantification of feeding intensity, via aphid-days (one aphid day: one aphid on a cabbage root for one day), was calculated and a functional relationship established between yield and aphid-days. This relationship indicated that plants would exhibit enough injury response to warrant the application of an insecticide treatment with as few as 300 aphid-days/plant. Maturation of greenhouse-grown broccoli was delayed by 9-11 days from feeding by an unrestricted infestation of PPGA and was further evidenced by the occurrence of differences in plant height between infested and uninfested broccoli at various plant ages. Rearing methods were developed for long-term colony maintenance and detailed biological studies of PPGA alienicolae. Development of alienicolae, and natality of fundatrigenia and alienicolae held at selected constant temperatures between 10-30°C responded directly to temperature. Alienicolae development ranged from 38-9 days, however, aphids reared under a fluctuating temperature regime developed faster than predicted by data collected at constant temperatures. Fundatrigenia exhibited a greater natality rate than adult alienicolae (7.2 versus 4.9 nymphs/day), but a lower gross capacity to produce young (18 versus 75 nymphs/female).