2,727 research outputs found

    Flutuação de infestação da broca-do-café (Hypothenemus Hampei, Ferrari) em Rondônia, 2002.

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    Introdução; Material e métodos; Resultados e discussão; Conclusões; Referências bibliográficas.bitstream/item/70954/1/BPD11-brocadocafe.pd

    Spiroacetals in the Colonization Behaviour of the Coffee Berry Borer: A 'Push-Pull' System

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    Coffee berries are known to release several volatile organic compounds, among which is the spiroacetal, conophthorin, an attractant for the coffee berry borer Hypothenemus hampei. Elucidating the effects of other spiroacetals released by coffee berries is critical to understanding their chemo-ecological roles in the host discrimination and colonization process of the coffee berry borer, and also for their potential use in the management of this pest. Here, we show that the coffee berry spiroacetals frontalin and 1,6-dioxaspiro [4.5] decane (referred thereafter as brocain), are also used as semiochemicals by the coffee berry borer for host colonization. Bioassays and chemical analyses showed that crowding coffee berry borers from 2 to 6 females per berry, reduced borer fecundity, which appeared to correlate with a decrease in the emission rates of conophthorin and frontalin over time. In contrast, the level of brocain did not vary significantly between borer-uninfested and infested berries. Brocain was attractive at lower doses, but repellent at higher doses while frontalin alone or in a blend was critical for avoidance. Field assays with a commercial attractant comprising a mixture of ethanol and methanol (1:1), combined with frontalin, confirmed the repellent effect of this compound by disrupting capture rates of H. hampei females by 77% in a coffee plantation. Overall, our results suggest that the levels of frontalin and conophthorin released by coffee berries determine the host colonization behaviour of H. hampei, possibly through a 'push-pull' system, whereby frontalin acts as the 'push' (repellent) and conophthorin acting as the 'pull' (attractant). Furthermore, our results reveal the potential use of frontalin as a repellent for management of this coffee pest.DF

    PATHOGENICITY TEST OF VARIOUS CONCENTRATIONS OF Beauveria bassiana CULTURED ON RICE BRAN AND CORN MEDIA AGAINST COFFEE FRUITS BORER (Hyphotenemus hampei)

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    Coffee is a commodity with high value for export. Coffee bean borer (Hypothenemus hampei) is the main pest causing the decline in coffee production. Farmers still rely on chemical insecticides to control this pest. To reduce the negative impact of insecticides, entomopathogen Beauveria bassiana is applied. The research aimed to investigating the level of pathogenicity of B. bassiana in controlling H. hampei, and investigating the concentration with the highest level of pathogenicity of B. Bassiana against H. hampei. Laboratory research was arranged in one factor Completely Random Design (CRD). This research used 8 (eight) treatments namely KO: Aquades, Kk: Lamda Sihalothrin 25 EC (Chemical Insecticide), B1: 10 g / L B. bassiana cultivated in rice bran media, B2: 20 g / L B. bassiana cultivated in rice bran media, B3: 30 g / L B. bassiana cultivated in rice bran media, B4: 10 g / L B. bassiana grown on corn media, B5: 20 gL B. bassiana grown on corn and B6: 30 g / L B. bassiana grown on corn media. Each treatment used coffee beans infested with 20 H. hampei and repeated 4 (four) times. The result of the research showed that B. bassiana was able to kill H. hampei. The concentration that was able to cause the fastest mortality with a high level of pathogenicity based on the pathogenicity test of B. bassiana on H. hampei (percentage of mortality, total mortality time, and feeding capacity) was 30 g/L of B. bassiana cultivated in rice bran media.Key words: Beauveria bassiana, Hypothenemus hampei, chemical insecticide, coffee bea

    Thermal Tolerance of the Coffee Berry Borer Hypothenemus hampei: Predictions of Climate Change Impact on a Tropical Insect Pest

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    Coffee is predicted to be severely affected by climate change. We determined the thermal tolerance of the coffee berry borer , Hypothenemus hampei, the most devastating pest of coffee worldwide, and make inferences on the possible effects of climate change using climatic data from Colombia, Kenya, Tanzania, and Ethiopia. For this, the effect of eight temperature regimes (15, 20, 23, 25, 27, 30, 33 and 35°C) on the bionomics of H. hampei was studied. Successful egg to adult development occurred between 20–30°C. Using linear regression and a modified Logan model, the lower and upper thresholds for development were estimated at 14.9 and 32°C, respectively. In Kenya and Colombia, the number of pest generations per year was considerably and positively correlated with the warming tolerance. Analysing 32 years of climatic data from Jimma (Ethiopia) revealed that before 1984 it was too cold for H. hampei to complete even one generation per year, but thereafter, because of rising temperatures in the area, 1–2 generations per year/coffee season could be completed. Calculated data on warming tolerance and thermal safety margins of H. hampei for the three East African locations showed considerably high variability compared to the Colombian site. The model indicates that for every 1°C rise in thermal optimum (Topt.), the maximum intrinsic rate of increase (rmax) will increase by an average of 8.5%. The effects of climate change on the further range of H. hampei distribution and possible adaption strategies are discussed. Abstracts in Spanish and French are provided as supplementary material Abstract S1 and Abstract S2
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