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.

Effects of a biocontrol agent of apple powdery mildew (Podosphaera leucotricha) on the host plant and on non-target organisms: an insect pest (Cydia pomonella) and a pathogen (Venturia inaequalis)

“…This effect was correlated with a change of the apple leaf surface primary metabolites (Derridj and Borges 2006). Moreover, it has been established that a change in soluble carbohydrates and sugar alcohols present on the leaf surface could partially explain a change in codling moth egg laying (Lombarkia and Derridj 2002) and it is known that epiphytic microorganisms consume the nutrients present on the leaf surface (Andrews 1992;Mercier and Lindow 2000). Therefore, we could expect a change in the leaf surface composition by the introduction of the epiphytic yeast and as a consequence a modification of the insect egg laying behaviour.…”

Foliar application of microdoses of sucrose to reduce codling moth Cydia pomonella L. (Lepidoptera: Tortricidae) damage to apple trees

“…The output and input of the sugars through the cuticle follow the photosynthesis rhythm. Once sprayed, the sugars can penetrate the leaf by transcuticular hydrophilic pores and induce some changes in apoplastic/cell sugar content and source‐to‐sink transition, increased cell‐wall invertase activity and also changes in the sucrose/hexose ratio in plants . At this point, plant immunity could be stimulated.…”

“…Although it remains to define precisely the role of phyllosphere microflora on the bioavailability of leaf sugars, several models predict the diffusion of sugars and other plant metabolites from the apoplast across the leaf cuticule and their consumption by epiphytic microorganisms . The studies show the important role of primary metabolites and particularly sugars on C. pomonella . Egg laying site preference within the apple tree and its intensity are related to a blend of three soluble carbohydrates (sucrose, D‐fructose and glucose) and three sugar alcohols (sorbitol, quebraquitol, myo ‐inositol) present at the surface of the apple tree.…”

“…Results concerning the role of sugars in the egg laying of C. pomonella , the efficacy of sugar application in apple orchards and the new concept of ‘sweet immunity’ still under investigation present challenges in exploiting sugars to reduce the susceptibility of plants to biopests. Our studies determined the efficacy of the foliar application of sucrose in microdoses against fruit damage due to C. pomonella .…”

Physical factors influencing the oviposition behaviour of European grapevine moths Lobesia botrana and Eupoecilia ambiguella

“…In other moth species, it might be possible that physical factors have a greater influence on the selection of an oviposition site than close‐range chemical cues (Foster, Howard, & Harris, ). The role of thigmotactic stimuli on oviposition has already been suggested for the tortricids Zeiraphera diniana (Bos & Baltensweiler, ) and Cydia pomonella (Lombarkia & Derridj, ).…”