摘要:

Data from three published studies on the development ofProstephanus truncatus(Horn) reared at constant temperatures and relative humidities (RH) were reanalysed to provide new information and quantitative description needed for predicting developmental times or rates in different environments. Models fitted to the temperature‐dependent development data were used for comparing developmental times among insect stages, relative humidities, diets and studies. Development of the eggs and pupae was similar at 40%, 70%, 80%, and 90% RH. Significant differences were detected between studies in the egg hatch to adult development and larval development, attributable, in part, to differences in the degree of compaction of ground maize used for rearing insects. For all life stages the temperatures for minimum (Tmin) and maximum (Tmax) developmental rates, and degree‐days aboveTminrequired for completion of development, were estimated. The linear degree‐day and nonlinear models presented here could be used for predictingP. truncatusdevelopment in the field. In conjunction with age‐specific fecundity and adult longevity data, these development models will be valuable in predicting population trends ofP. truncatusin the field. Predicting development and population trends is important for accurately timing insect sampling programmes and control tactics.

ISSN:0143-6147    

DOI:10.1080/09670879109371581

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

In a survey of cassava pests in a Préfecture of the Central African Republic, incidence and severity of cassava mealybug was generally low. Pest abundance was greatly influenced by cultural practices. Abundance was highest on compound farms and cassava fields near larger towns, where cassava is intensively grown. Cassava green mite was omnipresent. The damage caused by mite attack varied greatly between varieties. Some react by loss of tissue, causing a rapid reduction in mite population, others react by proliferation. Yield losses were estimated in the absence of yield data: losses caused by mealybug and green mite were low and less important than those caused by bacterial blight, mosaic, or adverse cultural practices.

ISSN:0143-6147    

DOI:10.1080/09670879109371582

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The banana skipper,Erionota torusEvans, was discovered for the first time as a new banana pest in Taiwan on September 1986. Monthly surveys indicated that within a year this hesperiid is well established and widely distributed in major banana‐growing areas of southern Taiwan. The infestation rates were higher in spring and autumn‐winter seasons, ranging from less than 5% to higher than 20% in different areas. A damage pattern of 1.11 (average) infested leaves per infested plant and 1.17 (average) rolls per infested leaf was found. With highly significant linear correlations between banana plant and leaf infestation rates versus skipper larvae and pupae counts in the field, a rapid and simple measurement to determine banana plant infestation rate (percentage) will be adapted for future studies on the population fluctuation and extent of damage.

ISSN:0143-6147    

DOI:10.1080/09670879109371583

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Based on the weekly male catches in pheromone traps and weather data for 2 years (1985, 1986), regression models were developed to predict the densities of melon fruit fly,Dacus cucurbitaeCoq., which is an important pest of cucurbit and solanaceous fruits. Among the simple linear regression models, the model SQRT (male counts + 1) = —5.37+0.75 (mean daily temperature in degrees Celsius) was the best, as it explained the highest (68%) variability. The model log(male counts + 1) = —7.54 + 0.35 (maximum temperature) + 0.63 (minimum temperature) —0.02 (maximum × minimum temperature) explained 80% variability, and was considered to be the best for forecasting fruit fly populations.

ISSN:0143-6147    

DOI:10.1080/09670879109371584

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Neem(Azadirachta indica)products were effective in protecting stored cowpeas against bruchid damage for over 4 months under artificial infestation in the laboratory. This practice, part of an extension package, is becoming popular with farmers. In field trials, aqueous neem seed extracts, as well as leaf extracts reduced thrips(Megalurothrips sjostedti)incidence in cowpeas and increased yields significantly. Extracts also had an adverse effect on the biology of the pod borer(Maruca testulalis).These findings have generated interest in a neem‐based pest management system for cowpeas and possibly other crops.

ISSN:0143-6147    

DOI:10.1080/09670879109371585

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Knockdown, mortality and residual activity of pyrethrins and cyfluthrin were studied on the larger grain borer (LGB),Prostephanus truncatus(Horn). Pyrethrum marc with 0.4% pyrethrins and cyfluthrin dust (0.1% a.i.) when applied on filter paper at 0.72 mg/cm2gave 98.6% and 100% knockdown (KD) respectively after 6 h. Cyfluthrin dust had a faster KD effect with 100% KD compared to 93.1% for pyrethrum marc, ½1/2>h after treatment. After 24 h there was no recovery from KD in both treatments. After 72 h, 23.2% of the LGB had recovered from KD while mortality was 76.8% in the pyrethrum marc treatment. After the same period, cyfluthrin resulted in 100% mortality. Mortality ofP. truncatusexposed to different dosages of cyfluthrin dust in shelled maize was less than 100% at dosages lower than 1 part per million (ppm) but was 100% at 1 ppm and higher dosages 3 days after treatment. Progeny emergence was suppressed at all dosage levels above 0.25 ppm compared to a mean progeny of 68.8 in the check after 45 days. Cyfluthrin dust was more residually toxic at 0.5 ppm and higher dosages, with mortality of >90% at 5 months after treatment. This suggests that cyfluthrin dust at 0.1% a.i. mixed with shelled maize at 1 ppm will give protection and control of LGB infestation.

ISSN:0143-6147    

DOI:10.1080/09670879109371586

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The responses of adult femaleHypothenemus hampeiresistant and susceptible to endosulfan were compared using a vapour exposure method at five temperatures, from 22°C to 34°C, for up to 10 h. Susceptible insects showed a rapid increase in mortality 2–4 h after exposure to concentrations above 100 ppm. Resistant insects were largely unaffected at all combinations of temperature and exposure time. The LC50of susceptibles declined with temperature, indicating a positive temperature coefficient. The method is recommended for early and reliable detection of endosulfan resistance after 6 h, at 25°C, with a concentration of 400 ppm.

ISSN:0143-6147    

DOI:10.1080/09670879109371587

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A field experiment to determine the insect pest profile for cowpea grown under residual soil moisture in’Rice Fadama ‘in the Bida area, northern Nigeria was carried out during the dry period of 1987 (February‐April). Elite IITA Cultivars TVx 3236 and IT84E‐1–108, with some resistance to flower thrips and aphids respectively, were used together with a local cultivar Dan llan in this study. Individual 15 m2plots were sprayed with Cymbush Super ED once to four times, coinciding with the major growth stages of the plant and attack by various insect pests. The key insect pests observed wereOothecabeetle, flower thrips and pod bugs in the foliage, bud formation and flowering and podding stages of plant growth respectively. Insect pressures were low, but flower thrips at bud formation and flowering was the most serious pest, and resulted in about 44% yield reduction. Yield reductions from insect attack at other plant stages singly or in combinations varied from 6% to 48%. Grain yields were 473, 484 and 700 kg/ha for TVx 3236, IT84–1–108 and Dan llan respectively. These yields may be a reflection of the cultivars’ drought tolerance and/or abilities to compensate for insect damage as indicated by higher fodder yields from unsprayed plots. However, considering the higher yields from unsprayed plots, despite the general low yields, high spray costs and farmers’ premium on fodder, chemical control was unprofitable. Thus, developing IPM practices with resistant cultivars and adjustment of planting date as the centrepiece would seem feasible for residual soil moisture cowpea production in this area.

ISSN:0143-6147    

DOI:10.1080/09670879109371588

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The seasonal abundance ofEnneadesmus obtusedentatusLesne (Col.: Bostrichidae) was studied on fig trees near Alexandria during 3 years, 1987, 1988 and 1989. Beetles started to emerge from late February/early March until late November/early December. About three broods per year were recorded. Infestation increased by almost three times throughout 2 years. Beetle emergence was positively related to temperature and negatively to relative humidity.

ISSN:0143-6147    

DOI:10.1080/09670879109371589

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Fish meal was used as attractant in four trap types for assessing the relative abundance and species composition of sorghum shoot flies, which are major pests in the wetter southern zones of Burkina Faso. Trapping was carried out in 1988 and 1989 during the rainy season in Bobo‐Dioulasso. Three trap models were effective in catchingAtherigona soccata:(1) water trap, (2) Multi‐Pher and (3) ICRISAT (International Crops Research Institute for Semi‐Arid Tropics) traps. Multi‐Pher and water traps were the most efficient. The advantages and disadvantages of each model are discussed. Identification of male flies demonstrated the presence of 34 species of the subgenusAtherigonaand two species of the subgenusAcritochaetawithAtherigona soccata, A. occidentalisDeeming andA. tomentigeravan Emden being predominant. Thirteen species were new records to Burkina Faso:A. aberransMalloch,A. africanaDeeming,A. fililobaDeeming,A. gabonensisDeeming,A. gilvifoliavan Emden,A. griseiventrisvan Emden,A. hyalinipennisvan Emden,A. medleriDeeming,A. nigrapicalisDeeming,A. pullaWiedemann,A. ruficornisStein,Acritochaeta yorkiDeeming. A new speciesAtherigona(s.s.) sp. n. will be described elsewhere.

ISSN:0143-6147    

DOI:10.1080/09670879109371590

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor