Efeito de inseticidas em diferentes fases de desenvolvimento de Grapholita molesta (Busck, 1916) (Lepidoptera: Tortricidae) e estruturas vegetais da macieira e do pessegueiro

Abstract

A mariposa-oriental Grapholita molesta é uma das principais pragas da macieira e do pessegueiro. Neste trabalho, foi avaliada a mortalidade causada por inseticidas quando aplicados sobre diferentes fases de desenvolvimento de G. molesta e sobre ponteiros e frutos de macieira e pessegueiro. Os inseticidas acetamiprido (8 g 100L-1), fosmete (100 g 100L-1), espinetoram (3,75 g 100L-1) e novalurom (4,0 g i.a 100L-1) reduziram a eclosão em níveis superiores a 80%, independentemente de a aplicação ser realizada em pré ou pós-oviposição. O etofenproxi (15 g 100L-1) foi mais eficaz quando aplicado em pós-oviposição. Em ponteiros de macieira e pessegueiro, os inseticidas acetamiprido, clorantraniliprole (4,9 g 100L-1), etofenproxi, fosmete, novalurom e espinetoram causaram mortalidade de lagartas acima de 90%. Em frutos de macieira, os inseticidas acetamiprido, clorantraniliprole, etofenproxi, fosmete e espinetoram causaram mortalidade de lagartas de 100; 79; 76; 97 e 100%, respectivamente, enquanto em frutos de pessegueiro apresentaram controle superior a 85%. O inseticida novalurom aplicado em frutos causou menor mortalidade das lagartas quando comparado à aplicação em ponteiros. Em adultos, apenas os inseticidas etofenproxi e fosmete foram tóxicos tanto a fêmeas (59 e 39%) quanto a machos (79 e 80%), enquanto o espinetoram mostrou efeito apenas em machos (78%). Conclui-se que os inseticidas etofenproxi, fosmete e espinetoram foram eficientes no controle de G. molesta em todas as fases de desenvolvimento.

Do Grapholita funebrana Infestation Rely on Specific Plum Fruit Features?

“…Despite that the use of resistant cultivars is strongly recommended in integrated pest management programs [80], genetic improvement programs that aim to identify sources of plum resistance to PFM are lacking, probably due to the high efficiency of the control methods commonly applied, like the use of chemical insecticides [81,82] and mating disruption [83,84].…”

Susceptibility, Oviposition Preference, and Biology of Grapholita molesta (Lepidoptera: Tortricidae) in Prunus Spp. Rootstock Genotypes

“…Therefore, P. kansuensis, which was the most infested genotype in the field and was preferred for greenhouse oviposition, was shown to be an adequate food source for the biological development of the insect when compared with Sharpe, similar to the results observed for the lesser peachtree borer S. pictipes (Cottrell et al 2008). Several studies have demonstrated that the source of food may influence the biological parameters of G. molesta (Myers et al 2006Joshi et al 2007Joshi et al , 2015Silva et al 2010;Chaves et al 2014). The lower oviposition preference for Sharpe may be associated with the presence of chemical compounds released by the leaves, the presence of physical barriers (such as hairs or glandular trichomes), and the shape of the leaves that provide an antixenotic or nonpreference effect for oviposition and infestation in the field (Lara 1991, Straub 2003, Al Bitar et al 2014, Joshi et al 2015.…”

“…The greater preference of natural infestation of G. molesta for the genotypes P. kansuensis, I-67-52-9, and I-67-52-4 may be associated with the narrow genetic base of these materials (Arge 2012) because P. kansuensis is a species of wild peach but is morphologically similar to the cultivated peach Prunus persica (Cao et al 2011), considered an ideal host species for the development of G. molesta (Silva et al 2010, Chaves et al 2014). This fact is reinforced by the low infestation observed in the Sharpe genotype, which is supposed to be a natural hybrid between the 0 Chickasaw 0 plum [Prunus angustifolia (Marsh.)]…”

“…At the end of the larval development, a piece of hydrophilic cotton was placed inside the cage to serve as a pupation site. To avoid escape of the larvae, another plastic cup (100 ml) was placed in the top of each cage in an inverted position, according to Chaves et al (2014). The experimental design was a completely randomized design with 100 replicates (larvae) per treatment.…”

“…The use of resistant host plants is recommended in integrated pest management programs (Kogan 1998). However, owing to the high efficiency of chemical insecticides (Arioli et al 2004, Chaves et al 2014 or mating disruption (Pastori et al 2012, Arioli et al 2014, genetic improvement programs aimed at finding sources of peach resistance to G. molesta are scarce. The identification of potential sources of peach resistance to G. molesta would help in the definition of new management strategies in the field and in nurseries, leading to a reduction in the application of insecticide for the control of the species.…”