Investigation of the effects of household processing on the reduction rate of chlorpyrifos, metalaxyl and diazinon residues in orange fruit

Summary The effect of the household processing on the reduction rate of chlorpyrifos, metalaxyl and diazinon residues in contaminated oranges has been investigated and the processing factors were determined. The evaluation included validation parameters, matrix effect (ME %), reduction behavior and processing factors (PFs). Validation parameters were successfully applied; the three pesticides showed satisfactory recovery (70–120%) and precision (relative standard deviation - RSD<20%); they also exhibited no matrix effect. The most effective process in the pesticide residues reduction was juicing, followed by pulping while the washing process was less efficient in removing all pesticide residues; sonication showed a high reduction rate with both chlorpyrifos and diazinon. The processing factors (PFs) were generally less than one which indicates that all processes can reduce pesticide residues in oranges. The results could guide the safe and reasonable use of chlorpyrifos, diazinon, and metalaxyl. These processes contribute substantially to reduce consumer exposure to pesticide residues in oranges.

Volatile organic compound profiling of Capsicum annuum var. longum grown under different concentrations of nitrogen

Summary Emission of volatile organic compounds (VOCs) in plants is triggered by several biotic and abiotic factors, such as nutrient deficiency, environmental stress, and pathogenic attacks. For instance, plants suffering from limited or excessive nitrogen (N) supply may experience internal stress which can ultimately lower their stability and immunity making them susceptible to infection and infestation. In this study, VOCs from Capsicum annuum var. longum (Solanaceae) exposed to nitrogen (1.8 g/L, 4.5 g/L, and 9 g/L urea) were extracted using a 100 μm Solid Phase Microextraction (SPME) fiber coated with polydimethylsiloxane (PDMS). Using Gas Chromatography-Mass Spectrometry (GC-MS), extracted VOCs from N-treated plants were identified as Butanoic acid, 3-hexenyl ester, (E)-; Butanoic acid, hexyl ester; Hexanoic acid, 3-hexenyl ester, (Z)-; Hexanoic acid, 4-hexen-1-yl ester; cis-3-Hexenyl cis-3-hexenoate and 4-Pentenoic acid 2-methyl-, hexyl ester. Among these volatiles, butanoic acid, 3-hexenyl ester showed the most distinctive peak from the N-treated plants in comparison with the untreated. In addition, the Green Leaf Volatiles (GLV) 3-Hexenal; 2-Hexenal; 3-Hexen-1-ol, (Z)-; 2-Hexen-1-ol, (E) and 1-Hexanol were also detected from the N-treated plants. The identification of plant volatiles provides useful information that can be used in agricultural practices and plant phenotyping.

Scale insect species (Hemiptera: Coccomorpha) and their natural enemies, recorded on agricultural, ornamental and forest plant species in the wider area of Messenian Province (Peloponnese, Greece), 2000 – 2020

Summary The scale insects (Hemiptera: Coccomorpha) recorded on agricultural, ornamental and forest plant species in the wider area of Messenian Province (Peloponnese, Greece) during the years 2000 – 2020 are reviewed. Twenty species were recorded, which belong to four families: Diaspididae: Aonidiella aurantii (Maskell), Chrysomphalus aonidum (L.), Diaspis echinocacti (Bouché), Dynaspidiotus abieticola (Koroneos), D. abietis (Schrank), Lepidosaphes beckii (Newman), L. gloverii (Packard), Lineaspis striata (Newstead), Targionia vitis (Signoret); Coccidae: Ceroplastes rusci (L.), Eulecanium sericeum (Lindinger), Nemolecanium graniformis (Wünn), Parthenolecanium corni (Bouché), P. persicae (Fabricius), Physokermes hemicryphus (Dalman), P. inopinatus Danzig and Kozár, Protopulvinaria pyriformis (Cockerell); Pseudococcidae: Phenacoccus madeirensis Green, Planococcus vovae (Nasonov) and Kermesidae: Kermes echinatus Balachowsky. The biology, phenology and natural enemies in Messenia are discussed for fifteen of these scale species.

Lethal and sublethal effects of several plant compounds compared to spiromesifen against Tetranychus turkestani

Summary Tetranychus turkestani Ugarov and Nikolski is one of the main agricultural pests of southwestern Iran and some other tropical regions. In the present study, fumigant activity of three essential oils extracted from Rosmarinus officinalis L., Mentha longifolia L. and Eucalyptus globulus Labill., and contact toxicity of two biopesticides (Tondexir and Palizin) on T. turkestani mite females were investigated and compared with that of spiromesifen, a chemical acaricide. Also, sublethal effects of the tested compounds at 50% lethal concentration (LC50) were estimated on the biological parameters of T. turkestani. The LC50 values for E. globulus, R. officinalis and M. longifolia essential oils were 12.50, 11.52 and 4.00 μl/l air and for spiromesifen, Tondexir and Palizin were 10.98, 327.34 and 858.13 ppm, respectively. All tested compounds significantly reduced adult female longevity, equally to the chemical acaricide spiromesifen. Fecundity also decreased in all treatments and this reduction was even higher for plant essential oils than the other compounds. Palizin, E. globulus and M. longifolia significantly reduced the hatchability of T. turkestani eggs similarly to spiromesifen. According to the results, the tested plant compounds are effective against T. turkestani and may be applied as suitable alternatives to synthetic pesticides against this crop pest.

Effects of gamma radiation and Bacillus thuringiensis on F1 progeny of Cydia pomonella

Summary The codling moth [Cydia pomonella L. (Lepidoptera: Tortricidae)] is the main pest in most apple orchards in Syria. It causes billions of dollars in loss of fruit crops every year. The present work examined the effects of gamma radiation and Bacillus thuringiensis (BT) on F1 progeny of C. pomonella. The experimental design was based on two factors, namely F1 offspring produced by males irradiated at a dose of 150 Gy, and artificial diet of BT-treated larvae. The first offspring of unirradiated and irradiated C. pomonella males, F1, were from parents treated with a commercial formulation of Bacillus thuringiensis BT (Dipel® 2X). F1 progeny of unirradiated was significantly less susceptible to BT than that of irradiated parents. The results showed high mortality in F1 progeny of C. pomonella when gamma radiation and BT were applied together. The LC50 in F1 progeny was 2.5 ppm for irradiated parents, while it was 13 ppm for unirradiated ones. A significant reduction in the fecundity and egg hatchability of F1 progeny of irradiated parents compared to unirradiated ones was observed. This study demonstrated that for F1 progeny the combination between Inherited Sterility Technique and BT can be useful to achieve an integrated pest management program of codling moth.