Heteroptera

Canatoxin (CNTX) is a variant form of urease isolated from Canavalia ensiformis (Leguminosaea) seeds. A possible role in the plant defense was proposed for CNTX, due to its toxicity upon feeding to the beetle Callosobruchus maculatus, and the hematophagous bug, Rhodnius prolixus. The toxic effect is caused by a canatoxin-derived peptide (w10 kDa) formed by insect cathepsin-like digestive enzymes. In order to evaluate their potential as bioinsecticides, the effects of CNTX and its peptide were evaluated on a phytophagous hemipteran insect Dysdercus peruvianus, a pest of cotton culture. For the bioassays, the insects fed on gelatin capsules containing powdered cotton seeds, mixed with the freeze-dried protein and other test materials and were observed for survival rate, weight gain and molting. Ingestion of canatoxin, or a recombinant 10 kDa peptide derived from it, severely affected young forms of the insects, delaying their development or leading to their death. In contrast, adults were insensitive to diets containing higher concentrations of canatoxin. Cathepsin-like proteinases predominated and showed distinct pattern of enzymatic activities in midguts homogenates according to the developmental stage of the insect, a fact which may explain the different susceptibility of nymphs as compared to adult D. peruvianus. The data presented confirm the potential use of canatoxin-like proteins and derived peptides as bioinsecticides. q

The generalist predator Orius laevigatus (Fieber) (Hemiptera: Anthocoridae) is a key natural enemy of various arthropods in agricultural and natural ecosystems. Releases of this predator are frequently carried out, and it is included in the Integrated Pest Management (IPM) programs of several crops. The accurate assessment of the compatibility of various pesticides with predator activity is key for the success of this strategy. We assessed acute and sublethal toxicity of 14 pesticides on O. laevigatus adults under laboratory conditions. Pesticides commonly used in either conventional or organic farming were selected for the study, including six biopesticides, three synthetic insecticides, two sulfur compounds and three adjuvants. To assess the pesticides' residual persistence, the predator was exposed for 3 d to pesticide residues on tomato sprouts that had been treated 1 h, 7 d or 14 d prior to the assay. The percentage of mortality and the sublethal effects on predator reproductive capacity were summarized in a reduction coefficient (E x ) and the pesticides were classified according to the IOBC (International Organization for Biological Control) toxicity categories. The results showed that the pesticides greatly differed in their toxicity, both in terms of lethal and sub lethal effects, as well as in their persistence. In particular, abamectin was the most noxious and persistent, and was classified as harmful up to 14 d after the treatment, causing almost 100% mortality. Spinosad, emamectin, metaflumizone were moderately harmful until 7 d after the treatment, while the other pesticides were slightly harmful or harmless. The results, based on the combination of assessment of acute mortality, predator reproductive capacity pesticides residual and pesticides residual persistence, stress the need of using complementary bioassays (e.g. assessment of lethal and sublethal effects) to carefully select the pesticides to be used in IPM programs and appropriately time the pesticides application (as function of natural enemies present in crops) and potential releases of natural enemies like O. laevigatus.

The western conifer seed bug, Leptoglossus occidentalis, is an alien invasive species of North American origin. Leptoglossus occidentalis was recorded for the first time in Arsoun-Metn, Lebanon in 2015. Adults and nymphs of L. occidentalis were collected by the authors from various locations in Lebanon and observed on two species of pine, Pinus pinea and Pinus brutia, on Juniperus excelsa and even on Cedrus libani. This could indicate its successful integration in the country and its presence on many coniferous tree species. Studies to investigate the behaviour and the economic impact of this alien insect species in Lebanon are recommended.

In this study six Heteroptera species are reported for the first time from Turkey; Dicyphus (Mesodiyphus) martinoi Josifov, 1958; Campylomma simillimum Jakovlev, 1882; Orthotylus (Melanotrichus) rubidus (Puton 1874); Orthotylus (Litocoris) ericetorum arboreae Wagner, 1969; Heegeria tangirica (Saunders, 1877) and Brachysteles parvicornis (Costa, 1847). Additionally a new synonymy is proposed; Orius (Heterorius) laticollis laticollis (Reuter, 1884) = Orius (Heterorius) laticollis discolor (Reuter, 1884) syn. n. and a remarkable color form of C. simillimum is mentioned.

Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) is a common natural predator of defoliating caterpillars in agricultural and forest systems. Insecticides acting as growth regulators of insect pests can indirectly affect their predators through consumption of contaminated prey. We examined the reproductive performance of P. nigrispinus fed on caterpillars of Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae) reared on soybean leaves exposed to the chitin synthesis inhibitor, diflubenzuron.

The present study was carried out to investigate the biocontrol potentiality of active ingredient isolated from ethyl acetate extract of mature leaves of Solanum nigrum L. ( S o l a na ce ae ) a g ain s t the l a r v al f o r m of Cu le x quinquefasciatus Say. Mortality rate at a concentration of 25 mg/L of the active compound was highest (P<0.05) amongst all tested concentrations. Result of log-probit analysis (at 95 % confidence level) revealed that LC 50 and LC 90 values are inversely proportional to exposure period of bioassay. A clear dose-dependent mortality was observed, as the rate of mortality (Y) was positively correlated with the concentrations of the compound (X); having regression coefficient value close to 1. The compound was found to be ecofriendly as it did not show any adverse effect to the studied nontarget organisms. Chemical characterization of the active ingredient was also carried out by infrared spectroscopic analysis (IR), mass analyses (GC-MS) and carbon-hydrogen-nitrogen-sulphur analyses (CHNS), that revealed the presence of a glucosinolate compound [1-thio-ß-D-glucopyranose-1-[(R)-3-hydroxy-2-ethyl-N-hydroxysulfonyloxy propanimidate] having the molecular formula of C 11 H 21 NO 10 S 2 .

A catalog of aquatic and semiaquatic Heteroptera from Iran is provided based on literature reports and field collections. Representatives of 107 species and morphospecies of the infraorders Dipsocoromorpha, Enicocephalomorpha, Gerromorpha, Leptopodomorpha, and Nepomorpha are listed, and are distributed in 18 families including Aphelocheiridae (1 genus, 1 species), Belostomatidae (1 genus, 1 species), Corixidae (8 genera, 29 species), Dipsocoridae (1 genus, 2 species), Enicocephalidae (2 genera, 2 species), Gerridae (6 genera, 18 species), Hebridae (1 genus, 5 species), Helotrephidae (1 genus, 1 species), Hydrometridae (1 genus, 2 species), Leptopodidae (4 genera, 7 species), Mesoveliidae (1 genus, 2 species), Naucoridae (1 genus, 1 species), Nepidae (3 genera, 5 species), Notonectidae (2 genera, 8 species), Ochteridae (1 genus, 1 species), Pleidae (1 genus, 1 species), Saldidae (5 genera, 14 species), and Veliidae (2 genera, 7 species). Synonyms and geographical distribution of all ...

The genus Leptoglossus in Guatemala is commented. Leptoglossus brevirostris, Leptoglossus crestalis and Leptoglossus tetranotatus are reported from Guatemala for the first time. New distributional data for Leptoglossus concolor, Leptoglossus dilaticollis, Leptoglossus gonagra, Leptoglossus subauratus and Leptoglossus zonatus are reported. A revised key to the known species of Leptoglossus from Guatemala is provided.