Compatibilidade de Fungos Entomopatogênicos com Inseticidas NicotinóidesRESUMO -O efeito fungitóxico, in vitro, de três inseticidas neonicotinóides, acetamiprid (Saurus 200 PS), imidacloprid (Confidor 700 GrDA) e thiamethoxam (Actara 250 WG) em três concentrações (RM = recomendação média para campo, 0,7 RM e 1,3 RM), foi avaliado sobre os fungos entomopatogênicos Beauveria bassiana, Metarhizium anisopliae e Paecilomyces sp. O efeito dos inseticidas sobre a germinação dos conídios, o crescimento vegetativo e a produção de conídios também foi avaliado. Os resultados mostraram que os produtos não afetaram a germinação dos conídios, com exceção do acetamiprid na maior concentração (1,3 RM) onde ocorreu uma inibição (P<0,05) de M. anisopliae. O crescimento vegetativo foi inibido nos tratamentos acetamiprid, nas três concentrações, para B. bassiana e M. anisopliae. Também no tratamento thiamethoxam, na concentração RM e 1,3 RM o crescimento vegetativo foi inferior à testemunha para B. bassiana. Para Paecilomyces sp. o crescimento vegetativo foi superior ao da testemunha para os tratamentos 0,7 RM e RM de acetamiprid, todas as concentrações de imidacloprid e as duas menores de thiamethoxam. A produção de conídios foi menor para o tratamento de acetamiprid na maior concentração (1,3 RM) para os fungos Paecilomyces sp. e M. anisopliae e para imidacloprid na maior concentração (1,3 RM) para Paecilomyces sp. Já thiamethoxam inibiu a produção de conídios somente na menor concentração (0,7 RM) para M. anisopliae. Aumento de produção de conídios foi observado somente nos tratamentos acetamiprid nas duas menores concentrações (0,7 RM) e RM e thiamethoxam nas duas maiores (RM e 1,3 RM) para o fungo Paecilomyces sp. Assim, os inseticidas testados nas concentrações e formulações utilizadas mostraram, na maioria dos casos, compatibilidade com os entomopatógenos B. bassiana, M. anisopliae e Paecilomyces sp. Portanto, estes produtos poderão ser recomendados em programas de MIP, nas formulações e concentrações testadas, para o controle de pragas que tenham como inimigos naturais os entomopatógenos testados. PALAVRAS-CHAVE: Insecta, Beauveria bassiana, Metarhizium anisopliae, Paecilomyces sp.ABSTRACT -The in vitro fungitoxic effect of the neonicotinoid insecticides acetamiprid (Saurus 200 SP), imidacloprid (Confidor 700 WDGr) and thiamethoxam (Actara 250 WG) in three concentrations (AR= average field recommendation; 0.7 AR and 1.3 AR) to the entomopathogenic fungi Beauveria bassiana, Metarhizium anisopliae and Paecilomyces sp. was studied. The effect of the insecticides on conidia germination, vegetative growth and conidiogenesis was compared. The insecticides had no effect on conidia germination, except under the highest concentration (1.3 AR) of acetamiprid, in which significant inhibition of M. anisopliae occurred. Vegetative growth of B. bassiana and M. anisopliae was significantly inhibited only by the three concentrations of acetamiprid treatment. Thiamethoxam treatment, in the AR and 1.3 AR concentrations, was significantly low...
The in vitro fungitoxic effect of three biofertilizers, Multibion TM and Supermagro used in organic agriculture and the neem oil (Azadirachta indica A. Juss) on the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana was studied. These products were mixed in a medium where the two fungi were inoculated, and germination, vegetative growth and conidiogenesis were assessed. The biofertilizers showed to be less toxic for the two fungi whereas Multibion™ caused major inhibition on M. anisopliae, with reductions in germination (-37.74%), colony diameter (-30.26%) and conidiogenesis (-42.62%). Neem oil promoted a larger negative effect on B. bassiana, inhibiting germination (-45.27%), colony diameter (-36.62%) and conidiogenesis (-84.93%).
In a survey of entomopathogenic nematodes in Brazil, a nematode isolate of the genus Heterorhabditis was found. The nematode was collected from soil by the insect-baiting technique and maintained in the laboratory on last instar Galleria mellonella (L.) larvae. Morphological and molecular studies of the isolate showed that the nematode is a new species. Light and scanning electron microscopy, DNA characterisation and phylogeny were used for this description. Heterorhabditis amazonensis n. sp. is morphologically similar to H. baujardi, H. floridensis, H. mexicana and H. indica, and can be distinguished from these species mainly by male and female characters. Fifty percent of Heterorhabditis amazonensis n. sp. males have two pairs of bursal papillae in the terminal group; 25% with two papillae on one side and one papilla on the other side and 25% with one pair of papillae. Twenty percent of the population has a curved gubernaculum. The percentage of the gubernaculum to spicule length (GS%) is lower than that of H. mexicana (50 vs 56), and the length of the spicule relative to anal body diam. (SW%) is lower than that of H. mexicana (152 vs 167) and H. baujardi (152 vs 182). The female can be differentiated from related species by its unique vulva pattern. In a phylogenetic tree, the new species, H. floridensis, H. baujardi and H. mexicana form a monophyletic group, a sister group to H. indica. The new species has evolved three autapomorphic nucleotide character states, differing from its sister taxa H. mexicana at 22, and H. baujardi at 15, aligned positions.
-The Mediterranean fruit fl y, Ceratitis capitata (Wiedemann), is considered one of the main pests that affect fruit production in the world. This insect spends part of its life cycle in the soil, making it a target for entomopathogenic nematodes. This work aimed at evaluating the infl uence of soil temperature and moisture on the infectivity of Heterorhabditis sp. RSC01 and Steinernema carpocapsae ALL to third-instars of C. capitata, and to compare the effi ciency of these isolates at fi ve different soil temperatures (19, 22, 25, 28, and 31°C) and three levels of relative soil moisture (100, 75, and 50% of fi eld capacity). Ten C. capitata larvae were transferred to plastic jars (12 cm × 6 cm) containing 100 g soil, followed by the application of an aqueous suspension containing 125 infective juveniles (IJ)/cm 2 . In the control treatment, 3 ml of distilled water was applied. Mortality evaluations were made fi ve days later and were confi rmed by observations of the characteristic symptoms and cadaver dissection. The infectivity was directly proportional to temperature increase, with maximum percent mortality of 86.7% and 80.0% for S. carpocapsae and Heterorhabditis sp., respectively, at 31°C. At 25°C, the highest mortality for both species was obtained at 75% of fi eld capacity (96.7% and 26.7% for S. carpocapsae and Heterorhabditis sp., respectively).
Seventy two isolates of Beauveria bassiana or Metarhizium anisopliae were screened for control of Sitophilus oryzae, S. zeamais (Col., Curculionidae), and Rhyzopertha dominica (Col., Bostrychidae). Beauveria bassiana isolates produced highest mortalities against all three hosts. Ten isolates (all B. bassiana) were selected for further experimentation in the second phase of selection process. Bioassays were conducted by inoculating 50 adult insects of each species, maintained at 26 OS'C, 70 f 10% RH, 12 h photophase, for 10 days. The cumulative mortalities after 10 days exposure and lethal time for 50% of the population (LT50) were calculated and compared. S. oryzae and S. zeamais were less susceptible to B. bassiana isolates than R. dominica, which was completely killed by several isolates. Isolate 476 was the most virulent to S. oryzae, and isolate 604 was the most virulent to S. zeamais. Isolate 604 was best overall, but isolates 476 and 643 should also be considered as control agents for stored-grain pests. A combination of isolates may be advantageous if mixed pest infestations occur.
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