First Evidence of Feeding-Induced RNAi in Banana Weevil via Exogenous Application of dsRNA

Banana weevil (Cosmopolites sordidus) is the most devastating pest of banana and plantain worldwide, yet current control measures are neither effective, sustainable, nor environmentally sound, and no resistant farmer-preferred cultivars are known to date. In this paper, we examined the ability to induce RNA interference (RNAi) in the banana weevil via feeding. We first developed an agar- and banana corm (rhizome) flour-based artificial diet in a multi-well plate setup that allowed the banana weevils to complete their life cycle from egg through the larval instars to the pupal stage in an average period of 53 days. Adults emerged about 20 days later. The artificial diet allowed the tunneling and burrowing habits of the larvae and successful metamorphosis up to adult eclosion. Adding dsRNA for laccase2 to the artificial diet resulted in albino phenotypes, confirming gene-silencing. Finally, C. sordidus was fed with dsRNA against a selection of essential target genes: snf7, rps13, mad1, vha-a, vha-d, and lgl for a period of 45 days. 100% mortality within 9–16 days was realized with dssnf7, dsrps13, and dsmad1 at 200 ng/mL artificial diet, and this corresponded to a strong reduction in gene expression. Feeding the dsRNA targeting the two vha genes resulted in 100% mortality after about 3–4 weeks, while treatment with dslgl resulted in no mortality above the dsgfp-control and the water-control. Our results have implications for the development of RNAi approaches for managing important crop pests, in that banana weevils can be controlled based on the silencing of essential target genes as snf7, rps13, and mad1. They also highlight the need for research into the development of RNAi for banana protection, eventually the engineering of host-induced gene-silencing (HIGS) cultivars, given the high RNAi efficacy and its species-specific mode of action, adding the RNAi approach to the armory of integrated pest management (IPM).

Evaluation of the Entomopathogenic Potential of Beauveria bassiana, Metarhizium anisopliae and Isaria fumosorosea for Management of Cosmopolites sordidus Germar (Coleoptera: Curculionidae)

The banana weevil (BW), Cosmopolites sordidus, is the main coleopteran pest of banana, causing up to 100% yield loss. In this study, we screened 20 isolates of entomopathogenic fungi (EPF) for the management of BW. In the lab, eight Beauveria bassiana isolates caused >50% mortality of the adult BW, whereas Metarhizium anisopliae and Isaria fumosorosea isolates were less pathogenic. B. bassiana isolates ICIPE 648, ICIPE 660 and ICIPE 273 were the most pathogenic, killing ≥80% of adult BW. B. bassiana isolate ICIPE 622 yielded the highest spores per BW cadaver (1.84 × 108 spores), followed by ICIPE 660, ICIPE 273 and ICIPE 648—1.17 × 108, 3.8 × 107 and 3.6 × 107 spores, respectively. ICIPE 273 had the shortest LT50 (5.3 days) followed by ICIPE 648 (9.8 days) and 660 (11.1 days). Similarly, the LC50 values for the three isolates were 5.18 × 107, 5.49 × 107 and 5.2 × 107 spores mL−1, respectively. In the field, ICIPE 273 and ICIPE 648 had the highest (31.3%) and lowest (20.8%) pathogenicity, respectively. This study indicates that the B. bassiana isolates ICIPE 273, ICIPE 648 and ICIPE 660 are potential candidates for the environmentally sustainable management of BW.

Controle biológico do gorgulho da bananeira Cosmopolites sordidus Germar com a utilização de diversas cepas de Beauveria bassiana em condições de laboratório / Biological control of the banana weevil Cosmopolites sordidus Germar with the use of several Beauveria bassiana strains under laboratory conditions

O gorgulho da bananeira Cosmopolites sordidus (Germar, 1824) (Coleoptera: Curculionidae) é uma praga de importância econômica no cultivo da bananeira, portanto, novas alternativas são necessárias para reduzir sua incidência. O estudo foi realizado no ambiente do Laboratório de Entomologia da Faculdade de Ciências Agrárias da Universidade Técnica de Babahoyo, onde foi avaliada a eficácia de diversas cepas de B. bassiana no controle de C. sordidus em condições de laboratório. Foram utilizados 12 tratamentos, que se baseiam na aplicação de diversas cepas de B. bassiana e um controle químico com diferentes doses, com três repetições por tratamento, distribuídos em um ensaio de blocos completos casualizados, onde foram feitas as comparações das médias com os Teste de intervalo múltiplo de Tukey a 95% de probabilidade. Os insetos C. sordidus foram coletados nas fases larva, pupal e adulta dos rebentos de bananeiras afetadas no campo, as quais foram desinfetadas com hipoclorito de sódio a 0,5%, para evitar qualquer tipo de contaminação. As larvas e pupas foram submetidas a completar seu ciclo biológico até a obtenção do adulto. A inoculação do fungo nos insetos adultos de C. sordidus foi realizada por micropulverização com micropipetas, na parte dorsal do inseto adulto com 5 dias de emergência. Os insetos adultos inoculados foram colocados em placas de Petri com 30 gramas de pseudocaule e 30 gramas de rizoma fresca, previamente desinfetados. Para cada tratamento, 5 insetos adultos foram colocados com três repetições, avaliando-se a cada 5, 8, 10 dias após a inoculação. Para estimar corretamente os efeitos dos tratamentos, foram coletados dados sobre o número de insetos mortos, a porcentagem de insetos adultos com crescimento de micélio de B. bassiana e a porcentagem de mortalidade. Pelos resultados obtidos, determinou-se que o tratamento 8 (BbPLUS (B. bassiana) 11,5 ml / L) e o tratamento 9 (BbPLUS (B. bassiana) 12,5 ml / L) apresentaram mortalidade de 80% em adultos de gorgulho preto após 8 e 10 dias após a inoculação.

THE EFFECT OF CONCENTRATION AND FREQUENCY OF APPLICATION OF BANAN WEEVIL SOLUTION KEPOK ON RED CHILI

The purpose of the study is to determine the effect of concentration and frequency of application of banana weevil solution kepok against red chili plants is roofed with translucent ultraviolet plastic 70% which acts as a natural growth regulator. Research on the provision of banana weevil solution covered in 70% translucent ultraviolet plastic in open land has not been found before. The growing regulators from the gibberellin and cytokinin groups were able to boost the growth and yield of chili peppers. The method of using a random design of factorial groups, as the first factor is age consists of 9 levels, namely T1: age (14) HSPT, T2: age (14.21) HSPT, T3: age (14,21,28) HSPT, T4: age (14,21,28, 35) HSPT, T5 : age (14,21,28,35, 42) HSPT, T6: age (14,21,28,35,42,49) HSPT, T7: age (14,21,28,35,42,49,56) HSPT, T8: age (14,21,28,35,42,49,56,63) HSPT, and control (T0). The second factor is concentration consists of 3 levels, namely K1 (30%), K2 (45%), and K0 (0%). The results of the study obtained concentration of K1 (30%) with the amount of T6 administration is the best result in vegetative growth of the plant height change, the number of branches, and the width of the header, while the concentration of K1 (30%) give the best results on the length of the fruit, the dry weight of the fruit, and the diameter of the fruit from other treatments. Conclusion of the application of concentration and frequency of the sea of banana weevil kepok containing regulatory substances growing on red chili plants in the field covered with ultraviolet plastic roof significantly increases the growth and yield of red chili peppers.

Evaluation of Physical quality of alang-alang (Imperata cylindrical) fermentation as fed greenswamp buffalo

The objectives of this study were to evaluate the physical quality of alang-alang (Imperata cylindrical) fermented using Banana Weevil Mol pH, color, aroma and texture. This research method using experimental methodswith completely randomized desig consists of 6 treatments repeated 3 times. L1 : Banana Weevil Mol 20 ml L2 : Banana Weevil Mol 25 ml L3 : Banana Weevil Mol 30 ml L4 : Banana Weevil Mol 35 ml L5 : Banana Weevil Mol 40 ml L6 : Banana Weevil Mol 45 ml.The results obtained were analyzed using analysis of variance and then the BNJ continued test. Based on the results of this study, it was shown that the physical quality of reeds fermented using banana weevil moles had a very significant effect (P <0.01) on pH parameters.significant effect (P <0.05) on color treatment and no significant effect (P> 0.05) on aroma and texture treatment parameters.Based on the research, it can be concluded that evaluating the physical quality of Imperata in the 35 ml L4: Banana Weevil Mole treatment gave the best results in all observation parameters.