Acibenzolar-S-methyl (ASM) is a chemical compound, which is able to induce resistance in several model and non-model plants, but the end-players of this induced defense remain ill-defined. Here, we test the hypothesis that treatment with ASM can protect apple (Malus × domestica) against the rosy apple aphid (Dysaphis plantaginea) and investigate the defense molecules potentially involved in resistance. We measured aphid life traits and performed behavioral assays to study the effect of ASM on plant resistance against the aphid, and then combined transcriptomic, bioinformatics, metabolic and biochemical analyses to identify the plant compounds involved in resistance. Plants treated with ASM negatively affected several life traits of the aphid and modified its feeding and host seeking behaviors. ASM treatment elicited up-regulation of terpene synthase genes in apple and led to the emission of (E,E)-α-farnesene, a sesquiterpene that was repellent to the aphid. Several genes encoding amaranthin-like lectins were also strongly up-regulated upon treatment and the corresponding proteins accumulated in leaves, petioles and stems. Our results link the production of specific apple proteins and metabolites to the antibiosis and antixenosis effects observed against Dysaphis plantaginea, providing insight into the mechanisms underlying ASM-induced herbivore resistance.

The rosy apple aphid, Dysaphis plantaginea (Passerini) (Hemiptera: Aphididae), is one of the major pests of European apple orchards, commonly controlled by the use of synthetic insecticides. In the present work, the non-protein amino acid DL--aminobutyric acid (BABA), known to induce plant resistance against a wide range of abiotic and biotic stresses, has been tested for its protective effect against this pest on apple. We first verified the lack of any contact effect of BABA on the insect itself. Next we applied BABA as a soil drench to apple and monitored its effect on the population development of aphids after artificial infestation. We demonstrated that BABA strongly reduced the population growth and that this compound severely affected various life-history characteristics of the aphid such as female longevity and fecundity, nymph mortality, and larval development.

Cacopsylla pyri (pear psylla) is one of the most serious pests of pear (Pyrus spp.) in Europe. It can cause high yield losses, and its control has become difficult since it has developed resistance to a wide range of pesticides. Pear breeders are developing new cultivars resistant to pear psyllids, and Asian species, such as Pyrus ussuriensis and Pyrus × bretschneideri, are good sources of resistance. Antixenosis and antibiosis resistance to psylla were both identified in pear; they may differ in the biological mechanism and probably have different genetic backgrounds. We crossed interspecific P. × bretschneideri × Pyrus communis hybrid PEAR3, resistant to pear psylla, with the susceptible European pear cultivar ‘Moonglow’ to obtain an F1 population for the genetic mapping of the resistance. Quantitative trait locus (QTL) analysis was carried out for antibiosis by measuring the number of surviving nymphs and the nymphal development, using a novel phenotyping protocol and a saturated genetic map made of single-nucleotide polymorphism (SNP) and microsatellite (simple sequence repeats (SSR)) markers. A stable QTL was detected on linkage group (LG) 8 of PEAR3 (R 2 = 17.2–39.1 %). In addition, QTLs were detected on LG5 (R 2 = 10.8 %) of PEAR3 and on LG15 of ‘Moonglow’ (R 2 = 13.7 %).

Pear psylla is a very important problem in French pear orchards. Resistant cultivars would offer an alternative to chemical control. However all major cultivars grown in France are susceptible to Caeopsylla pyri. Some Pyrus inter-specific hybrids are known to be resistant to pear psylla; yet, the bad quality of the fruits limit the usefulness of these genotypes in breeding programs. To identify other resistant genotypes, screening of 16 genotypes of Pyrus was conducted in a mesh-covered tunnel during 4,5 months. The cultivar 'Williams known' to be sensitive to pear psylla, was considered as susceptible control. The hybrids 'Katman' and 'NY10355' were considered as resistant controls. The observations were carried out on 7 or 8 plants per genotype. The eggs were recorded on the eight upper leaves of the shoots 15 days after the release of adults in the tunnel. The nymphs were recorded on the eight upper leaves of the shoots, 36, 63 and 98 days after infestation. The shoot and the leaf states were recorded after 134 days. Several inter-specific hybrids ('BP6', 'BP81', 'Gutui' and 'P20R5A70') were identified as highly resistant. Our results confirm also the resistance of 'Spina Carpi', an old Italian cultivar. Furthermore, three P communis were newly identified as resistant: the 'Doyenne de Poitiers', the 'D'Aout Lamer' and the hybrid 'SEL80-79-69' ('Docteur Jules Guyot' x 'Bella di Giugno'). However, these genotypes exhibited medium levels of resistance to pear psylla.

RésuméRésuméL'étude des différentes étapes comportementales qui mènent à l'oviposition chez S. nonagrioides montre que les déplacements à distance sont caractérisés par un vol en zigzag qui remonte le flux d'air. Après l'atterrissage sur la plante, la femelle effectue des contacts antennaires et balaye la surface du végétal avec l'extrémité abdominale. Cette prospection prend fin quand l'extrémité abdominale entre en contact avec la fente d'une gaine foliaire; les oeufs sont alors déposés dans cette fente. L'oviposition se produit majoritairement au début de la première nuit consécutive à la nuit de l'accouplement. La présence d'oeufs conspécifiques sur le maïs n'influence pas le choix du site de ponte, que ce soit à distance ou au contact.AbstractOviposition behaviour of Sesamia nonagrioides Lefebvre (Lepidoptera: Noctuidae). Effect of conspecific eggs. — S. nonagrioides behaviour is described according to the different stages leading to oviposition. Flight in the wind tunnel is characterised by a zigzag trajectory against the flow. Once landing on maize, the female evaluates the surface of the plant with the antennae and the abdomen tip. This prospection step ends when the abdominal tip makes contacts with the slit of the leaf sheath. The abdominal tip is introduced into the slit and the oviposition begins. Females lay a large majority of eggs during the first night following the mating night, mostly at the beginning of the scotophase. The presence of conspecific eggs on maize, whether at a long range or in contact, does not have an effect on the choice of the oviposition site.Mots-clés: féconditélocalisationmaïsplante-hôteprospectiontrajectoiretunnel de vol

S. nonagrioides behaviour is described according to the different stages leading to oviposition. Flight in the wind tunnel is characterised by a zigzag trajectory against the flow. Once landing on maize, the female evaluates the surface of the plant with the antennae and the abdomen tip. This prospection step ends when the abdominal tip makes contacts with the slit of the leaf sheath. The abdominal tip is introduced into the slit and the oviposition begins. Females lay a large majority of eggs during the first night following the mating night, mostly at the beginning of the scotophase. The presence of conspecific eggs on maize, whether at a long range or in contact, does not have an effect on the choice of the oviposition site.

Before oviposition, Östrinianubilalis Hübner females sweep the surface of the plant with their abdominal tip extruded. The consequences of such behaviour were studied on host searching and oviposition behaviours of the parasitoidTrichogramma brassicae Bezdenko. Egg-masses ofO. nubilalis, associated or not with sweeping, were submitted toT. brassicae females. The behaviour ofT. brassicae females appeared to be very different between the two situations. The parasitoid in the vicinity of an egg-mass associated with sweeping spent more time on the corn leaf. Ninety percent of females located the egg-mass with sweeping, whereas only 40% located the egg-mass without sweeping. Eighty three percent ofT. brassicae females parasitized egg-masses with sweeping, but only 10% in the case without sweeping. Although no deposit was visible, a chemical trail was probably left behind and was found to arrest the parasitoid, to promote host recognition and to trigger oviposition. The amount of the scales left behind on the corn leaf during the sweeping behaviour was also taken into account but did not appear to constitute the trail. The passage over the trail followed by the egg-mass examination constituted behavioural steps which seemed necessary for oviposition in theT. brassicae female

Our study sought to assess how much phosphorus (P) runoff from paddy fields could be cut down by fertilizer management and inoculation with arbuscular mycorrhizal fungi. A field experiment was conducted in Lalin River basin, in the northeast China: six nitrogen–phosphorus–potassium fertilizer levels were provided (0, 20%, 40%, 60%, 80%, and 100% of the recommended fertilizer supply), with or without inoculation with Glomus mosseae. The volume and concentrations of particle P (PP) and dissolved P (DP) were measured for each runoff during the rice growing season. It was found that the seasonal P runoff, including DP and PP, under the local fertilization was 3.7 kg/ha, with PP, rather than DP, being the main form of P in runoff water. Additionally, the seasonal P runoff dropped only by 8.9% when fertilization decreased by 20%; rice yields decreased with declining fertilization. We also found that inoculation increased rice yields and decreased P runoff at each fertilizer level and these effects were lower under higher fertilization. Conclusively, while rice yields were guaranteed arbuscular mycorrhizal inoculation and fertilizer management would play a key role in reducing P runoff from paddy fields.

The susceptibility of Oryctes rhinoceros adults to infections due to entomopathogenic fungi (Beauveria bassiana, Beauveria tenella, Metarrhizium anisopliae, Paecilomyces fumoso-roseus, and Spicaria rileyi) was studied by spraying titrated spores suspensions on the insect integument. The results show a definite susceptibility of the adults to Metarrhizium anisopliae strains of the major type only.