Problemele combaterii dăunătorilor la culturile agricole în spații protejate

Climate change is becoming increasingly unpredictable as the climate dries up, protected areas grown with vegetables are growing every day, but farmers in this area are facing a number of problems, including pests of green cucumber lice (Aphis gossypii), the common thrips. (Thrips tabaci), the common red spider (Tetranychus urticae). Scientists around the world are conducting studies to propose solutions. The use of material that allows the passage of a larger amount of UV rays inhibits the development of aphid colonies. The dual application of Lecanicillium longisporum for the simultaneous suppression of green lice of cucumbers and powdery mildew has been demonstrated. Beauveria bassiana preparations are highly effective against tripe. For a future assured with high quality vegetables, it is necessary to develop as diverse methods as possible to control pests, so that each farmer can choose the method that suits him, both technologically and economically. The methods should be applicable in the most diverse areas of the earth. We must learn to model not only favorable climatic conditions but to create a healthy and viable ecosystem, so the greenhouses will generate profit for the farmer, fresh and tasty products for us.

Reporte del estado sexual de Lecanicillium longisporum en Melanaphis sacchari

Antecedentes: Durante la búsqueda de enemigos naturales de Melanaphis sacchari en Tecomán, Colima, México, se observaron poblaciones micosadas de pulgón amarillo en sorgo; tres meses después se encontraron estructuras fúngicas de reproducción sexual desarrollándose en la región dorsal abdominal de algunos pulgones.Objetivo: Dar a conocer por primera vez el estado teleomorfo de Lecanicillium longisporum, desarrollado sobre M. sacchari en Colima, México.Métodos: Se utilizaron técnicas de microscopía para el análisis morfológico de los peritecios encontrados sobre M. sacchari. Para la caracterización molecular se utilizó la región its y el gen rpb1. Resultados y conclusiones: Los peritecios encontrados en los pulgones momificados con L. longisporum son morfológicamente diferentes a Cordiceps confragosa y otras especies reportadas como teleomorfos de Lecanicillium. Las secuencias its y rpb1 mostraron 100% de similitud con las secuencias del anamorfo che-cnrcb 620 (its: kx426564; rpb1: kx426566) de L. longisporum. La identificación molecular confirmó que los peritecios corresponden al teleomorfo de la misma especie, siendo el primer reporte del estado sexual de L. longisporum.

Susceptibility of the Japanese beetle, Popillia japonica (Newman) (Coleoptera: Scarabaeidae), to entomopathogenic Hypocreales fungi

The susceptibility of adults and larvae of the Japanese beetle to isolates of the fungi Beauveria bassiana, B. brongniartii, Metarhizium anisopliae, Lecanicillium longisporum and L. muscarium (Ascomycota: Hypocreales) was evaluated in laboratory bioassays. The presence of intra- and interspecific variations regarding the pathogenicity of the isolates was investigated. Results show that most of the fungal isolates caused mortality in adults and larvae. Isolates M. anisopliae INRS 705 and B. bassiana INRS 236 induced 70.3% and 65.2% of mortality in P. japonica adults, respectively, and both caused the death of about 37% of larvae. Of the 17 tested isolates, 13 caused larval mortality. However, no significant difference was found between the susceptibility of larvae to isolates from different species and those from a same species. Lecanicillium species are undoubtedly not pathogenic to adults and seem to have few effects on larvae. Based on the results obtained with the selected isolates, intra- and interspecific differences relative to the pathogenicity of the isolates appeared to be present. Overall, this study expanded the knowledge about P. japonica susceptibility towards entomopathogenic Hypocreales fungi. The implications of this study regarding the development of a biological control agent are discussed.

Pathogenicity of the fungus Lecanicillium longisporum against Sipha maydis and Metopolophium dirhodum in laboratory conditions

This study aimed to evaluate the susceptibility of two cereal aphids, Sipha maydis (Passerini) and Metopolophium dirhodum (Walker), to the entomopathogenic fungus, Lecanicillium longisporum (Zimm.) Zare and Gams strain LRC 190, under controlled conditions. The conidial suspension of the fungus was administered using a sprayer on the whole plant over apterous adult aphids. The results indicated that both aphid species were susceptible to L. longisporum and that aphid populations were significantly reduced, compared to the control. Nine days after treatment, the LC50 value of the fungus was obtained as 5.9 × 105 and 3.2 × 106 conidia/ml for S. maydis and M. dirhodum, respectively. The LT50 value of the fungus at a concentration of 108 conidia/ml was obtained as 2.9 and 4.4 days for S. maydis and M. dirhodum, respectively. The results demonstrated that there was a varying susceptibility to the fungus between aphid species. The estimated LC50 and LT50 indicated that L. longisporum was more virulent to S. maydis than to M. dirhodum. The LT50 and R0 decreased as the conidial concentration increased. This is the first study to demonstrate the susceptibility of S. maydis to the entomopathogenic fungi. The present study suggests that L. longisporum has high virulence against the aphids S. maydis and M. dirhodum. Further research with an emphasis on greenhouse and field tests are required, however, before making any decision about using the fungus in a control program