Development of efficient integrated management package against sweet potato weevil (Cylas formicarius [Fabricius, 1798])

<p class="042abstractstekst">The sweet potato weevil (<em>Cylas formicarius</em>, 1798) is one of the most damaging sweet potato pests. To prevent an economic crop loss, it is very important to develop a suitable and efficient integrated pest management strategy. A field experiment was set up with three replications at Jamalpur to select the best integrated management package from eight different treatments against sweet potato weevil. The results showed that the lowest percentage of infestation by number (2.94 %) and mass (3.22 %) was found when the crop was planted on November 01; earthing-up for two times, Carbofuran 5G was sprayed @ 15 kg ha^-1 at 60 days after planting with irrigation and tuber was harvested at 130 days after planting. The marketable yield (23.75 kg) and percent increase of yield than control (50.86 %) performed the highest in the same combination. These findings suggested an effective integration of different management strategies to reduce sweet potato weevil infestation in Bangladesh successfully.</p>

Screening of Five Lamiaceae Essential Oils as Repellents for Sweet Potato Weevil, Cylas Formicarius (F.) (Coleoptera: Brentidae)

In this research, the repellent activity of five Lamiaceae essential oils, Agastache rugosa, Elsholtzia blanda, Elsholtzia ciliata, Elsholtzia penduliflora, and Plectranthus ovatus, was evaluated against sweet potato weevil, Cylas formicarius using a two-choice test between the essential oil-treated filter paper and the control. E. blanda and A. rugosa essential oils have some sweet potato weevil attractant properties at low dose (<47.16 nl/cm2),while N,N-diethyl-3-methylbenzamide (DEET), P. ovatus, E. penduliflora, and E.ciliata essential oils have repellent properties at doses ranging from 15.72 nl/cm2 to 196.49 nl/cm2. The effect of type of essential oil and their dose were interactively associated with repellent efficacy. There was a increase in repellent efficacy as the dose increased for all essential oils. The repellent activities of P. ovatus essential oil and E. penduliflora were higher than the others, and the repellent effects of E. ciliata essential oil and DEET were more dose-dependent than others, indicating that at low dose, P. ovatus and E. penduliflora essential oils have stronger repellent efficacy, but at higher dose DEET and E. ciliata have greater effects. Our findings clearly demonstrate that P. ovatus, E. penduliflora, and E. ciliata essential oils are candidate materials for future investigation as repellent compounds against sweet potato weevil control.

Laboratory and Greenhouse Evaluation of Melia volkensii Extracts for Potency against African Sweet Potato Weevil, Cylas puncticollis, and Fall Armyworm, Spodoptera frugiperda

The African sweet potato weevil, Cylas puncticollis, and fall armyworm, Spodoptera frugiperda, are insect pests of economic importance that have a negative impact on sweet potato and maize production, respectively. In this study, we aimed to evaluate the potential of Melia volkensii extracts to protect sweet potato and maize plants against damage by both insect pests. We evaluated extracts from the bark, leaves, pulp and nuts of Melia volkensii for antifeedant activity against C. puncticollis and S. exigua (used as a substitute for S. frugiperda), under laboratory conditions. Interestingly, extracts of all plant parts showed antifeedant activity. These results led us to investigate the effectiveness of nut and pulp extracts to protect sweet potato and maize crops in greenhouse conditions. Against C. puncticollis, the sweet potato plants treated with nut extracts showed the lowest tuber damage (18%) when compared to pulp extracts (30%), positive control (33%) and negative control (76%). Nut extracts, pulp extracts and positive control reduced maize leaf and whorl damage by S. frugiperda compared to the negative control. Altogether, this study highlights the potential of M. volkensii extracts and their application in integrated insect pest management

Development of useful integrated management package against sweet potato weevil.

The sweet potato weevil (Cylas formicarius Fab.) is one of the most damaging sweet potato pests. To prevent an economic crop loss, it is very important to develop a suitable and efficient integrated pest management strategy. A field experiment was set up with three replications at Jamalpur to select the best-integrated management package from eight different treatments against sweet potato weevil. The result showed that the lowest percentage of infestation by number (2.94%) and weight (3.22%) was found when the crop was planted on November 01; earthing-up for two times, Carbofuran 5G was sprayed @ 15 kg/ha at 60 days after sowing with irrigation and tuber was harvested at 130 days after planting. The marketable yield (23.75 kg) and percent increase of yield than control (50.86%) performed highest in the same combination. These findings suggested an effective integration of different management strategies to reduce sweet potato weevil infestation in Bangladesh successfully.

Effects of Storage Periods of an Artificial Larval Diet on the Yield and Quality of Mass-Reared West Indian Sweet Potato Weevil (Coleoptera: Curculionidae)

Artificial diets have been employed for the mass-rearing of numerous insects because of their ease of use and standardized quality. An ability to store artificial diets under nonrefrigerated conditions over the long term could improve the efficacy of mass-rearing systems considerably. However, it remains largely unknown how long artificial diets can be stored at such temperatures without any adverse effects on the insects reared. In this study, we investigated yield, body size, and reproductive potential of West Indian sweet potato weevil, Euscepes postfasciatus (Fairmaire), which is a major sweet potato pest, under management using the sterile-insect technique in Japan and reared using artificial diets with different storage periods (14, 28, and 42 d) at nonrefrigerated temperatures (25 ± 1°C), and compared them with those of the control (0 d). Notably, E. postfasciatus yield and reproductive potential increased significantly with an increase in storage period (28 and 42 d). Conversely, male body size decreased significantly following feeding with artificial diet stored for 42 d, when compared with the control, while there were no significant differences in female body size between the control and all the treatments. We discuss the potential causes of such varying effects between yield and body size and conclude that E. postfasciatus artificial diet can be stored for at least 28 d without any adverse effects on weevil yield and weevil quality. To the best of our knowledge, this is the first report revealing the positive effects of long-term storage of the artificial diet on mass-reared insects.