Incidence of apple fruit and leaf surface metabolites on Cydia pomonella oviposition

Abstract

Water soluble metabolites identified from surfaces of apple tree fruit and leaf stimulate oviposition in Cydia pomonella L. The effects of two artificial blends of primary metabolites representing fruit and leaf surfaces, respectively, and of components within the blends were examined on egg-laying after two time periods: 3 min and 25 min of darkness. An artificial mixture of six metabolites, viz., three sugar alcohols (sorbitol, quebrachitol, and myo-inositol) and three sugars (glucose, fructose, and sucrose) did stimulate egg-laying. Fructose, sorbitol, and myo-inositol are important components of the stimulatory blend. Contact durations may induce variations in egg-laying responses. After 3 min of darkness, there were no differences in numbers of females laying eggs nor in the numbers of eggs laid on cloths treated with the complete blends and the controls. There were, however, clear effects of groups of compounds and of individual compounds. Reduced blends without sugars and sugar alcohols were in many cases significantly less stimulatory than the complete blends and the controls. After 25 min of darkness, the proportions of females laying eggs as well as the numbers of eggs were higher after treatment with the complete blends than on the controls. The proportions of females laying eggs on cloths treated with the reduced blends were rather similar to the controls, whereas there were still significant effects on the numbers of eggs laid after treatment with reduced blends derived from fruits but not from leaves.

A test of fruit varieties on entry rate and development by neonate larvae of the codling moth, Cydia pomonella

“…In addition, sucrose content, a potential correlate with host food quality, was analyzed for the apples used in larval performance experiments. It was hypothesized that (1) the establishment success of codling moth larvae varies across host plant species; (2) the establishment and subsequent performance of neonate codling moth larvae differ across intraspecific host plant varieties; and (3) a corresponding difference in average sugar content exists among apple varieties (Lombarkia & Derridj, 2002). Thus, the specific research objectives were fourfold: (1) to determine the frequency of larval entry into the fruits of four host plant species (apple, pear, quince, and walnut); (2) to determine the frequency of larval entry into three varieties of apple (Golden Delicious, Granny Smith, and Red Delicious); (3) to determine larval development times and biomass of emergent adults relative to apple varieties; and (4) to quantify sucrose concentration in the apple varieties used herein.…”

Resistance of apple trees to Cydia pomonella egg‐laying due to leaf surface metabolites

“…During that period of time, 50% of the females laid eggs on the control (8.8 ± 1.01). Observations of the egg-laying behaviour of the insect on the apple tree under cages and in no-choice conditions showed that the egglaying 'decision' is rather short, varying according to the plant part, and does not exceed 5 min (Lombarkia, 2002;Lombarkia & Derridj, 2002). Females always scan with their ovipositor before laying eggs (Lombarkia, 2002).…”

“…Among primary metabolites, soluble carbohydrates resulting from photosynthesis, such as glucose, fructose, and sucrose, and sugar alcohols, such as sorbitol, quebrachitol, and myo -inositol, have been found on apple [ Malus domestica Borkh. (Rosaceae)] leaves and fruits, where they act as signals for C. pomonella site acceptance and egg-laying stimulation (Derridj et al, 1999b;Lombarkia & Derridj, 2002). Within the blend of these six metabolites, fructose and sorbitol were the most influential.…”

Allelochemicals in Plant–Insect Interactions

“…Their oviposition responses to maize, however, have been reported to differ greatly in different cultivars; some compounds that deter female oviposition have been suggested to occur in resistant cultivars. 31 A more recent investigation has revealed that gravid females of the oriental fruit moth, Cydia molesta, which also causes severe damage to stone fruit and pome fruit, were attracted to a mixture of three GLVs ((Z)-3hexen-1-ol, (E)-2-hexenal, and (Z)-3-hexenyl acetate), benzaldehyde, and benzonitrile 32 identified from peach shoot extract. 28,29 The host orientation of the codling moth, Cydia pomonella (Tortricidae), a major pest of apple (Malus domestica; Rosaceae) and stone fruit, is thought to be guided by volatiles emitted from larval host fruit.…”

“…Although both wasps are attracted to dummies scented with chiloglottone, N. cryptoides more preferred those located at higher position from the ground than N. monticola did. This flower biosynthesizes (Z)-11-eicosen-1-ol (31), which is known as the alarm pheromone component from the sting of honeybees. 138 To date, six chiloglottone derivatives have been isolated from 20 Chiloglottis species, with these orchids containing single or dual chiloglottone component(s).…”