Etude du comportement de ponte du carpocapse (Cydia pomonella L.) (Lepidoptera ; Tortricidae) sur deux varietes de pommier (Malus domestica BORKH.)

Le carpocapse, Cydia pomonella L. (Lepidoptera : Tortricidae) figure parmi les principaux ravageurs des pommes et des poires dans la région de  Batna (Algérie). Le présent travail montre la première étude, à l’échelle nationale, sur le comportement de ponte de ce ravageur. La souche  utilisée a été récupérée d’un verger situé dans la région de Tazoult  (Batna). Le choix de deux variétés de pommier (Golden Delicious et Starkrimson), du point de vue de la ponte en conditions naturelles et le choix de la région de Tazoult, réside dans le fait que dans cette région, ces deux variétés sont sensibles au carpocapse. L’observation du comportement de ponte du carpocapse sur arbre, en milieu naturel et en conditions de non-choix dans la région de Limbiridi (Batna), confirme que la variété Golden Delicious est plus sensible à la ponte que la variété Starkrimson. Différentes étapes comportementales sont observées sur les deux variétés étudiées : atterrissage à la surface du pommier, visite des différents sites, examen du site et l’acceptation de ponte. La ponte est accompagnée par l’examen du site par balayage de l’ovipositeur.Mots-clés : Lepidoptera, Cydia pomonella, Golden Delicious, Starkrimson, comportement de ponte. The codling moth, Cydia pomonella L. (Lepidoptera : Tortricidae) is the major pest of apples and pears in the region of Batna (Algeria). This work is the first nationally study about codling moth egg-laying behavior.  Insects used in the study have been collected from the region of Tazoult (Batna). Counting eggs on the two apple tree varieties (Golden Delicious and Starkrimson) in choice conditions in the region of Tazoult (Batna) showed that both varieties are susceptible to codling moth egg-laying, with a slight preference of Golden Delicious. The observation of egg-laying behavior of codling moth on trees in natural and non-choice conditions in the region of Limbiridi (Batna), confirmed that Golden Delicious variety is more preferred for egg-laying than Starkrimson. Different behavioural steps are observed on both studied varieties : landing on the surface of apple tree, visiting different sites, site examination and acceptance of egg-laying. The egglaying is accompanied by an examination of the site by scanning of the ovipositor.Key words : Lepidoptera, Cydia pomonella, Codling moth, Golden  Delicious, Starkrimson, egg-laying behavior

Variability influence of the volatile compounds of three algerian date cultivars (Phoenix dactylifera L.) on infestation rates of the date moth [(Ectomyelois ceratoniae Zell. (Lepidoptera: Pyralidae)]

The date moth Ectomyelois ceratoniae Zeller (Lepidoptera; Pyralidae) is a serious pest for the dates production in Algerian oasis. Its dangerousness resides in its wide geographic distribution on various bioclimatics stages and his polyphagia on various hosts. In this context, to find out the impact of the dates volatile compounds on the date moth oviposition behavior. To do this, we conducted the following study, which is divided into two parts, one in the field and the other in the laboratory. This study investigated the effect of the biochemical profiles of three Algerian date cultivars (Deglet-Nour, Ghars and Degla-Beidha) on the infestation rates of the date moth. The monitoring infection rates in the field produced the following results: during the campaigns from 2011/2012 to 2014/2015 at the INRAA Sidi Mahdi-Touggourt station (Algeria), revealed that the cultivar Deglet-Nour is the most affected with a rate of 18.84%, followed by Ghars with 10.28% then Degla-Beidha with 6.66%. As for the extracts analysis of the three date cultivars with hexane were identified and quantifie via coupling gas chromatography / mass spectrometry (GC/MS). The analysis of the volatile compounds of the cultivars studied allowed to identify 110 compounds distributed in eight chemical classes (hydrocarbons (saturated aliphatic hydrocarbons, unsaturated aliphatic hydrocarbons, unsaturated monocyclic hydrocarbons, saturated monocyclic hydrocarbons, aromatic hydrocarbons, terpene hydrocarbons), alcohols, aldehydes, esters, ketones, amides, phenols and carboxylic acids), whose compounds are distributed as follows: 72 compounds for the Deglet-Nour, 38 compounds for the cultivar Ghars and 29 compounds for Degla-Beidha

Putative Chemosensory Receptors of the Codling Moth, Cydia pomonella, Identified by Antennal Transcriptome Analysis

The codling moth, Cydia pomonella, is an important fruit pest worldwide. As nocturnal animals, adults depend to a large extent on olfactory cues for detection of food and mates, and, for females, oviposition sites. In insects, odor detection is mediated by odorant receptors (ORs) and ionotropic receptors (IRs), which ensure the specificity of the olfactory sensory neuron responses. In this study, our aim was to identify chemosensory receptors in the codling moth as a means to uncover new targets for behavioral interference. Using next-generation sequencing techniques, we identified a total of 43 candidate ORs, one gustatory receptor and 15 IRs in the antennal transcriptome. Through Blast and sequence similarity analyses we annotated the insect obligatory co-receptor ORco, five genes clustering in a conserved clade containing sex pheromone receptors, one homolog of the Bombyx mori female-enriched receptor BmorOR30 (but no homologs of the other B. mori female-enriched receptors) and one gene clustering in the sugar receptor family. Among the candidate IRs, we identified homologs of the two highly conserved co-receptors IR8a and IR25a, and one homolog of an IR involved in phenylethyl amine detection in Drosophila. Our results open for functional characterization of the chemosensory receptors of C. pomonella, with potential for new or refined applications of semiochemicals for control of this pest insect

Formulation of the endophytic fungus Cladosporium oxysporum Berk. and M.A. Curtis, isolated from Euphorbia bupleuroides subsp. luteola, as a new biocontrol tool against the black bean aphid (Aphis fabae Scop.)

Two formulations containing culture filtrates and conidial suspensions of the endophytic fungus Cladosporium oxysporum Berk. & M.A. Curtis, isolated previously from stems of Euphorbia bupleuroides subsp. luteola (Kralik) Maire, were experimentally tested for their aphicid activity against the black bean aphid Aphis fabae Scop. found in Algeria. It was shown that invert emulsions are more effective against aphids, than using aqueous suspensions. This was especially true for formulations containing culture filtrates. The relatively insignificant mortalities obtained by formulations containing conidial suspensions indicated a low infectious potential towards the aphids. The proteolytic activity seemed to be more important than the chitinolytic activity of the fungus against the black bean aphid A. fabae

Effect of a granulovirus larvicide, Madex®, on egg-laying of Cydia pomonella L. (Lepidoptera: Tortricidae) due to changes in chemical signalization on the apple leaf surface

Applications of Madex® (granulovirus) against the codling moth, Cydia pomonella, which targets neonate larvae before or during their initial entry into fruit, provide selective control of this key apple pest. Differences in the efficacy of Madex® treatment against C. pomonella larvae were observed in an experimental orchard in northern Italy on two apple tree cultivars, ‘Golden Delicious’ and ‘Red Chief’. The intensity of egg-laying by the moth may vary from one cultivar to another. The composition of a metabolite blend on the leaf surface consisting of glucose, fructose, sucrose, sorbitol, quebrachitol and myo-inositol is one of the factors that could explain these variations. Our hypothesis was therefore that variations in the efficacy of Madex® could be related to variations in egg numbers, itself related to the composition of metabolites on the leaf surface of each cultivar. Differences in egg-laying (number and localization) were recorded on the two cultivars, ‘Golden Delicious’ and ‘Red Chief’, untreated or treated with the larvicide. Madex® had the same efficacy on both cultivars in terms of the reduction of fruit damage due to larval feeding. Surprisingly, the effect ofMadex® on reducing damage seemed less tied to a lethal effect of the larvicide on the larvae than to egg-laying reduction, the latter being linked to changes in chemical signals of the leaf surface induced by applications of Madex®. This observation was verified by experiments on egg-laying on an artificial substrate. When the active metabolite blends mimicking the corymb leaf surface compositions of each cultivar (untreated and treated with Madex®) were applied to nylon cloth egg-laying substrates, significant reductions in acceptance (% of egg-laying females) and egg-laying stimulation (number of eggs per egg-laying female) were observed. The reduction of eggs on ‘Red Chief’ could be primarily explained by a drastic effect on egg-laying stimulation, whereas the reduction on ‘Golden Delicious’ was partly due to a lower acceptance. The number of eggs laid naturally differs from one apple tree cultivar to another. The effects of reduced egg-laying caused by applications ofMadex® were due to biochemical changes in surface blends, depending on the cultiva