Survival rates of neonate larvae of the spiny bollworm,Earias insulana Boisd., on leaves, flower buds and bolls of ten high-gossypol (HG) [terpenoid-aldehyde] and Acala SJb2 cotton lines were 40-74%, 66-92% and 54-76%, respectively. Partial resistance of leaves of three cotton lines, no resistance of flower buds, and resistance of bolls of one line (HG-BR-8) to larval infestation were observed. Bolls which had their bases and bracts removed were heavily penetrated by larvae and more adults were obtained on them, as compared with intact ones. Complete development on cotton bolls, from hatching to the adult, took 25.6-32.6 days, with significant differences among some of the cotton lines. Growth on bolls of HG lines in the larval stage had no effect on oviposition by the corresponding adults. Fertility of these eggs was not affected. 相似文献
Three insect growth regulators (IGR), the chitin synthesis inhibitors (CSI) teflubenzuron and hexaflumuron and the juvenile hormone mimic (JHM) pyriproxyfen, as well as the organophosphate (OP) pirimiphos-methyl, were evaluated for their activity against the cowpea weevil, Callosobruchus maculatus (F), in cowpea seeds stored for up to 8 months post-treatment. The initial activity data showed that, based on LC50 level, teflubenzuron had strong ovicidal activity (LC50 = 0.056 mg kg(-1)) followed by pirimiphos-methyl (1.82 mg kg(-1)) and pyriproxyfen (91.9 mg kg(-1)). The residual activity data showed that none of the IGRs tested had strong activity when applied at 200 mg kg(-1) in reducing the oviposition rates of C maculatus at various storage intervals up to 8 months post-treatment. However, teflubenzuron reduced adult emergence (F1 progeny), achieving control ranging from 96.2% at 1 month to 94.3% at 8 months. Hexaflumuron showed a similar trend in its residual activity, ranging between 93.8% control at 1 month to 88.2% control at 8 months post-treatment. However, pyriproxyfen was more active than the CSIs tested and caused complete suppression (100% control) of adult emergence at all storage intervals. Unlike the IGRs tested, pirimiphos-methyl applied at 25 mg kg(-1) was more effective in reducing oviposition rates of C maculatus up to 8 months post-treatment. A strong reduction of adult emergence was also observed at various bimonthly intervals (98.6% control at 1 month to 91.6% control at 8 months post-treatment). The persistence of hexaflumuron and pirimiphos-methyl in cowpea seeds was also studied over a period of 8 months. The loss of hexaflumuron residue in treated cowpeas (200 mg kg(-1)) was very slow during the first month post-treatment (4.43%). At the end of 8 months, the residue level had declined significantly to 46.4% of the initial applied rate. The loss of pirimiphos-methyl residue in treated cowpeas (25 mg kg(-1)) was relatively high during the first month post-treatment (36.7%) and increased to 81.6% after 8 months. 相似文献
The effects of (Z)-11-hexadecenyl trifluoromethyl ketone (Z11-16:TFMK) a fluorinated pheromone analogue, on the responses to sex pheromone of the male cabbage armyworm, Mamestra brassicae, have been investigated in an actograph and by electroantennography (EAG). In spite of its structural proximity with the natural pheromone, Z11-16:TFMK was poorly active in EAG, and not active on male behaviour. When permeated in the air, Z11-16:TFMK reversibly inhibited the electroantennographic responses to (Z)-11-hexadecenyl acetate (Z11-16:Ac), the main component of the sex pheromone. In the actograph, the latency of the activation was increased and the intensity of the behavioural activity of males in response to Z11-16:Ac was significantly reduced in the presence of Z11-16:TFMK. These results, along with others previously reported by us, provide new pointers to the possible use of Z11-16:TFMK in pest-control strategies. 相似文献
The oviposition responses of the diamondback moth, Plutella xylostella L., to Neemix 4.5, a neem-based oviposition repellent/deterrent, with or without previous experience were studied in the laboratory on plain aluminum foil sheets, on aluminum foil sheets coated with cabbage juice, and on cabbage plants. In the plain aluminum foil sheet experiment, the females without prior experience of Neemix (inexperienced females) deposited more eggs (66.2%) on sections with untreated sheets than on sections with Neemix-treated sheets (33.8%), indicating that the inexperienced females were significantly repelled and/or deterred by Neemix. In contrast, the Neemix-experienced females deposited more eggs (69.2-69.7%) on sections with Neemix-treated sheets than on sections with untreated sheets (30.3-30.8%), implying that the females were not repelled and/or deterred by Neemix following an experience. In the tests using egg-laying sheets coated with cabbage juice or with cabbage juice plus Neemix, the inexperienced females deposited more eggs (63.8%) on the sections with sheets treated with cabbage juice only than on the sections with sheets coated with cabbage juice and Neemix (36.2%), indicating that inexperienced females were repelled and/or deterred by Neemix. Similarly, Neemix-experienced females deposited more eggs (62.2-65.6%) on the sections with sheets treated with cabbage juice plus Neemix than on the sections with sheets treated with juice only (34.4-37.8%), suggesting that the females were not repelled and/or deterred by Neemix following an experience. On cabbage plants, inexperienced females oviposited similar numbers of eggs on both Neemix-treated (50.8%) and untreated plants (49.2%). However, the Neemix-experienced females oviposited more eggs on the plants treated with Neemix (56.3%) than on untreated plants (43.7%), indicating that the females were attracted by Neemix-treated plants following an experience. The significance of this study for applications of insect repellents/deterrents in pest management is discussed. 相似文献
ABSTRACT The effect of different combinations of temperatures and exposure times on the mortality of Heterodera schachtii eggs was assessed in two different experiments under laboratory conditions. In the first experiment, cysts in water were exposed to 25, 35, 37.5, 40, 42.5, 45, 47.5, 50, or 52.5 degrees C for a maximum period of 2 h. In the second experiment, cysts in naturally infested soil were exposed to 25, 32.5, 35, 37.5, 40, 42.5, or 45 degrees C for a minimum period of 2 h to a maximum of 2,048 h. Viability of eggs in cysts was assessed by a hatching test in 3 mM zinc chloride solution. Viability in water was suppressed after 2-h exposure at 50 degrees C and inhibited after 1 to 2 h at 52.5 degrees C. Emergence of juveniles from cysts in soil was greater at the lower temperature x exposure time combinations and suppressed at higher combinations. Egg mortality started after exposure for 256 h at 40 degrees C, 32 h at 42.5 degrees C, and 16 h at 45 degrees C, and 81, 31, and 7 h of exposure were necessary to kill 50% of the nematode egg population at 40, 42.5, and 45 degrees C, respectively. The data fitted the models P(t) = P(0)10(-t/ (q + mT)) and P(T1) = P(T0)10(-T/(z - pt)) for m = -0.0111, q = 0.8238, z = 2.444, and p = -0.23. 相似文献
ABSTRACT Modeling techniques were developed to quantify the probability of Tilletia indica entering and establishing in Western Australia (WA), and to simulate spread, containment, and the economic impact of the pathogen. Entry of T. indica is most likely to occur through imports of bulk grain or fertilizer (0.023 +/- 0.017 entries per year and approximately 0.009 +/- 0.009 establishments per year). Entry may also occur through straw goods, new or second-hand agricultural machinery, and on personal effects of travelers who have visited regions with infected plants. The combined probability of entry and establishment of T. indica, for all pathways of entry, is about one entry every 25 years and one establishment every 67 years. Alternatively, sensitivity analysis does show that increases in quarantine funding can reduce the probability of entry to about one entry every 50 years and less than one establishment every 100 years. T. indica is spread efficiently through contaminated farm machinery, seed and soil, rain, air currents, and animals. Depending on the rate of spread of the pathogen and the amount of resources allocated for detection, the time until first detection could range from 4 to 11 years and the economic impact could range from 8 to 24% of the total value of wheat production in WA. 相似文献
Rock hyraxes,Procavia capensis (Mammalia: Hyracoidea), were fed 0.005% brodifacoum in apple bait for 20 and 48 h in no-choice laboratory experiments. Death of three out of five animals took place (11-15 days after the feeding) after the consumption of 7.0-7.9 mg a.i./kg body weight in the 20-h feeding and in four out of four animals death occurred (6-9 days after the feeding) following the consumption of 5.7-15.4 mg/kg in the 48-h feeding. 相似文献
Phytoparasitica - The life cycle of the carob moth,Spectrobates (= Ectomyelois) ceratoniae (Zeller), was examined on stored almonds held at 26±1°C and 70±5% relative humidity.... 相似文献
Dianisylneopentane or 1,1-bis(p-methoxyphenyl)-2,2-dimethylpropane was metabolized largely by O-demethylation to form mono- and diphenol derivatives. Only a small percentage was degraded by α-hydroxylation and rearrangement. In the model ecosystem, dianisylneopentane reacted very similarly to methoxychlor, accumulating in fish to about the same extent and yielding a slightly higher ratio of polar to nonpolar metabolites. The neopentyl group proved to be approximately as stable in biological systems as the isosterically equivalent trichloromethyl group. 相似文献
Phytoparasitica - Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, is a devastating fungal disease in oilseed rape. Chemical control with fungicides is the primary method of controlling... 相似文献
The effects of pheromone components, pheromone dose in the dispenser, aging of dispenser in the field, and trap type on trapping efficiency of males of the honeydew moth,Cryptoblabes gnidiella (Mill.) (Lepidoptera: Pyralidae), were investigated. At dosages of 2 or 0.2 mg, a binary blend containing (Z)-11-hexadecenal (Z11–16: Aid) and (Z)-13-octadecenal (Z13–18:Ald) (1:1) was as effective in attracting males as a quaternary blend containing Zll-16:Ald, (E)-11-hexadecenal (Ell-16:Ald), Z13–18:Ald and (E)-13-octadecenal (E13–18:Ald), (10:1:10:1). Within the range of 20 to 2000 μg pheromone/dispenser, response of males increased positively with the pheromone dose; however, a load of 10 or 20 mg/dispenser was significantly less attractive to males than 2 mg/dispenser. The effect of aging of the dispenser in the field on trapping efficiency was significant. Captures in traps baited with 3- and 4-week-old septa were lower than those in traps baited with 1- or 2-week-old septa. The gradual loss of attractancy exhibited by rubber septa indicates that septa should be renewed within 2-3 weeks. The release rate of the pheromone was measured in a flow system and monitored with Zl1– 16:Ald only. The emission was almost constant for 18 days and then decreased gradually until the 34th day. The nonsticky IPS trap was as effective in capturing honeydew moth males as the sticky Pherocon 1C trap. The possibility of using the nonsticky, non-saturating and easy-to-handle IPS traps may lead to better and easier monitoring of honeydew moth populations. 相似文献
Precipitation, a natural feature of weather systems in the Earth, is vitally important for the environment of any region. Under global climate change condition, the characteristics of precipitation have changed as a consequence of enhanced global hydrological cycle. The source region of the Yellow River(SRYR), locating within the Qinghai-Tibet Plateau, is sensitive to the global climate change due to its complex orography and fragile ecosystem. To understand the precipitation characteristics and its impacts on the environment in the region, we studied the characteristics of rainy days and precipitation amount of different precipitation classes, such as light(0–5 and 5–10 mm), moderate(10–15, 15–20 and 20–25 mm) and heavy(≥25 mm) rains by analyzing the precipitation data of typical meteorological stations in the SRYR during the period 1961–2014, as well as the trends of persistent rainfall events and drought events. Results showed that annual average precipitation in this area had a non-significant(P>0.05) increasing trend, and 82.5% of the precipitation occurred from May to September. Rainy days of the 0–5 mm precipitation class significantly decreased, whereas the rainy days of 5–10, 10–15, and 20–25 mm precipitation classes increased and that of ≥25 mm precipitation class decreased insignificantly. The persistent rainfall events of 1-or 2-day and more than 2-day showed an increasing trend, with the 1-or 2-day events being more frequent. Meanwhile, the number of short drought periods(≤10 days) increased while long drought periods(>10 days) decreased. Since the 0–5 mm precipitation class had a huge impact on the grasslands productivity; the 5–10, 10–15, and 20–25 mm precipitation classes had positive effects on vegetation which rely on the deep soil water through moving nutrients and water into the root zone of these vegetation or through the plant-microbe interactions; the ≥25 mm precipitation class contributed to the floods; and more persistent rainfall events and fewer long drought events inferred positive effects on agriculture. Thus, these results indicate grassland degradation, less risk of floods, and the upgrading impact of climate change on agriculture. This study may provide scientific knowledge for policymakers to sustain the eco-environmental resources in the SYSR. 相似文献
The cover image, by Derek Farnsworth et al., is based on the Research Article Economic analysis of revenue losses and control costs associated with the spotted wing drosophila, Drosophila suzukii (Matsumura), in the California raspberry industry, DOI: 10.1002/ps.4497 . Photo Credit: Kathy Keatley Garvey, Dept of Entomology and Nematology, UC Davis.
