Sex Pheromone Traps for Monitoring the European Vine Moth,Lobesia botrana: Effect of Dispenser Type,Pheromone Dose,Field Aging of Dispenser,and Type of Trap on Male Captures

The effects of dispenser type, pheromone dose in the dispenser, aging of dispenser in the field, and trap type on trapping efficiency of males of the European vine moth,Lobesia botrana Den. et Schiff. (Lepidoptera: Tortricidae), were investigated. LB Pherocon caps and locally manufactured septa were equally effective in attracting males to traps. Within the range of 0.1 to 100 μg pheromone/dispenser, response of males increased positively with the pheromone dose. Within the first 7 days tested, pheromone loads of 1 or 10 mg/dispenser were significantly less attractive to males than 0.1 mg/dispenser. The effect of aging of the dispenser (loaded with 1 mg pheromone) in the field on trapping efficiency was significant. Captures in traps baited with 4- and 5-week-old septa were significantly lower (by 24%) than those in traps baited with 1-week-old septa. The fairly slow loss of attractancy exhibited by rubber septa indicates that septa may be kept in traps for at least 5 weeks. The release rate of the pheromone from the Israeli dispensers (1 mg loaded) was measured in a flow system. The emission of the pheromone decreased gradually as a function of age, correlating well with the lower trap catches of field-aged septa. Release rates were reduced by 56%, 70% and 84% after 4, 5 and 6 weeks, repectively. The nonsticky IPS trap was as effective in capturing the European vine moth males as the sticky Pherocon 1C trap. The possibility of using the non-sticky, nonsaturating and easy-to-handle IPS traps may lead to better and easier monitoring of the European vine moth populations.     

Association of the inhibitor of virus replication with resistance mechanisms in pepper cultivars

The kinetics of accumulation of tobacco mosaic virus (TMV) and the S strain of pepper mild mottle virus (PMMV) in resistant and susceptible pepper cultivars was analyzed by enzyme-linked immunosorbent assay (ELISA). Crude protein extracts from noninoculated leaves of the resistant cultivar significantly inhibited TMV replication in tobacco protoplasts. Inoculation with either TMV or PMMV-S caused a slight increase in its inhibitory potency. In contrast, protein extracts from either inoculated or noninoculated leaves of the susceptible cultivar did not inhibit TMV replication in tobacco protoplasts. The protein extracts from the resistant cultivar gave a positive reaction with antibodies against the tobacco inhibitor of virus replication (IVR) in western blotting. The putative role of this IVR-like protein from the resistant cultivar in resistance against TMV is discussed.     

Suppression of powdery mildew in squash by applications of whitewash,clay and antitranspirant materials

The incidence of powdery mildew, caused bySphaerotheca fuliginea (Schlecht. Fr.) Polacci, in squash plants, was suppressed in the field to 50–60% of that in untreated control plants by weekly sprays with whitewash (Loven or Yalbin) or clay. Loven or Yalbin sprays resulted in significant reductions in disease level, more on the adaxial (59–65%) than on the abaxial (38–52%) surface of leaves, and more on young (53–59%) than on old (12–18%) leaves. The addition of 0.1% Dabak (a commercial sticker) to the whitewashes significantly increased their efficiency (22% above that of the controls), the degree of protection being associated with whitewash concentration. Squash leaves were protected from powdery mildew also by weekly sprays of the antitranspirant Vapor Gard, to a level comparable with that achieved by a whitewash plus sticker. However, the protection levels achieved with whitewashes, clays and antitranspirant were lower than with a fungicide (propiconazole). Experiments conducted under controlled conditions resulted in higher rates of escape from infection and a lower rate of hyphal and conidial development on plants and tissues following whitewash, clay and antitranspirant treatments.     

Effect of endotoxic compounds isolated fromVerticillium lecanii on the sweetpotato whitefly,Bemisia tabaci

Toxic products extracted by methanol from intact mycelia ofVerticillium lecanii were tested for their toxicity to eggs, larvae, pupae and adults ofBemisia tabaci and additional insects. All stages ofB. tabaci were sensitive to the toxin, with larvae showing the highest, and adults the lowest, sensitivity. Using a 0.5% crude toxin preparation, the mortality rate ofB. tabaci was 88%, 53.5%, 53.2% and 37% for larvae, eggs, pupae and adults, respectively. High sensitivity of adults, which was characterized by rapid paralysis followed by death, was observed inB. tabaci, Myzus persicae, Aphis gossypii, Acyrthosiphon pisum andFrankliniella occidentalis. Other insects,viz., Heliothis peltigera, Maladera matrida, Carpophilus hemipterus andCeratitis capitata, exhibited significantly lower sensitivity. The toxin was partially purified by differential extraction with organic solvents and on silica gel H and Sephadex LH 20 columns. Based on the toxin inactivation by saponification and its mobility in a polar solvent on thin layer chromatography, it is suggested that the toxic products might be phospholipids.     

Laboratory transmission of the citrus stubborn disease agent by a leafhopper from theCirculifer tenellus complex from the Jordan Valley

Citrus stubborn disease (=little leaf disease) is known to affect the size of citrus trees, and to reduce the quality and quantity of the fruit. The disease agent,Spiroplasma citri, was isolated and culturedin vitro from Oroblanco, orange and grapefruit orchards throughout the year from different regions in Israel. The agent was transmitted by a leaf-hopper from theCirculifer tenellus complex collected onAtriplex halimus plants in the southern Jordan Valley. The latent period of the agent in this vector was at least 10 days following a 3-day acquisition feeding onMatthiola incana plants. It was similar to that found for a primary isolation in culture medium (LP₅₀=21 days). The limitations of visual inspection for recording disease incidence in citrus groves were determined and this method was compared with other methods for detection of the disease agent (immunoassay and cultivation in a culture medium). Plants from various botanical families were tested for their ability to serve as hosts for the Israeli biotype of the beet leaf-hopper and for the stubborn disease agentS. citri. The possible role of IsraeliC. tenellus in the disease epidemiology is discussed.     

Seedborne infection ofAscochyta rabiei in chickpea and its transmission to aerial plant parts

Ascochyta blight of chickpea (Cicer arietinum L.), caused byAscochyta rabiei (Pass.) Labrousse, was found to be both externally as well as internally seedborne in nature, with the external infection being predominant. The pathogen was located primarily on or in the seed coat and in very few cases penetrated into the cotyledons and rarely, to the embryo. Seedling infection resulted from both externally as well as internally seedborne inoculum. The mode of fungal transmission from seed to the foliar plant parts was strictly non-systemic in nature.     

Effects of Neem Seed Derivatives on Brown Planthopper Symbiotes

Populations of intracellular symbiotes declined significantly in brachypterous females of the brown planthopper,Nilaparvata lugens (Stål), which were stressed during nymphal development by caging them on IR20 rice plants treated with 3% neem oil, 5% neem seed kernel aqueous extract, or 10% neem cake aqueous extract. In addition, nymphs grew poorly and symbiote populations in prospective females declined, when reared on rice plants grown in soil treated with neem cake; this indicates systemic action of bioac-tive neem constituents. Addition of custard-apple oil to neem oil did not enhance the inhibitory effects. The effects of neem derivatives on the symbiotes may be either host-mediated — possibly through disturbed neuroendocrine homeostasis, or direct — leading to perturbations of host-symbiote equilibrium.     

Sex pheromone traps for monitoring the honeydew moth,Cryptoblabes gnidiella: Effect of pheromone components,pheromone dose,field aging of dispenser,and type of trap on male captures

The effects of pheromone components, pheromone dose in the dispenser, aging of dispenser in the field, and trap type on trapping efficiency of males of the honeydew moth,Cryptoblabes gnidiella (Mill.) (Lepidoptera: Pyralidae), were investigated. At dosages of 2 or 0.2 mg, a binary blend containing (Z)-11-hexadecenal (Z11–16: Aid) and (Z)-13-octadecenal (Z13–18:Ald) (1:1) was as effective in attracting males as a quaternary blend containing Zll-16:Ald, (E)-11-hexadecenal (Ell-16:Ald), Z13–18:Ald and (E)-13-octadecenal (E13–18:Ald), (10:1:10:1). Within the range of 20 to 2000 μg pheromone/dispenser, response of males increased positively with the pheromone dose; however, a load of 10 or 20 mg/dispenser was significantly less attractive to males than 2 mg/dispenser. The effect of aging of the dispenser in the field on trapping efficiency was significant. Captures in traps baited with 3- and 4-week-old septa were lower than those in traps baited with 1- or 2-week-old septa. The gradual loss of attractancy exhibited by rubber septa indicates that septa should be renewed within 2-3 weeks. The release rate of the pheromone was measured in a flow system and monitored with Zl1– 16:Ald only. The emission was almost constant for 18 days and then decreased gradually until the 34th day. The nonsticky IPS trap was as effective in capturing honeydew moth males as the sticky Pherocon 1C trap. The possibility of using the nonsticky, non-saturating and easy-to-handle IPS traps may lead to better and easier monitoring of honeydew moth populations.     

Sex pheromone traps for detecting and monitoring the raisin moth,cadra figulilella,in date palm plantations

Field tests were carried out to determine whether pheromone traps, baited with (Z,E)-9,12-tetradecadienyl acetate (Z9,E12-14:Ac) impregnated in rubber septa (Maavit, Israel), could provide a reliable tool for monitoring the raisin moth,Cadra figulilella (Gregson), in date palm plantations. No significant differences were detected between captures of males in traps baited with 1 or 10 mg pheromone/dispenser. However, traps baited with 1 mg pheromone captured significantly more males than those baited with 0.1 mg pheromone/dispenser. No differences were found between captures of males in traps hung at a height of 8 m (near the bunches) or 2–3 m (on palm trunks). Two peaks of male capture were detected, one in May-June and the other during September-October (ripening period). Results indicate a positive relationship between captures in traps and infestation levels by larvae. Pheromone traps baited with 1 mg Z9,E12–14:Ac impregnated in rubber septa and hung on palm trunks (at a height of 2–3 m), were very useful for monitoringC. figulilella populations and for determining the accurate timing of insecticide applications.     

Effects of pheromone loading, dispenser age, and trap height on pheromone trap catches of the oriental fruit moth in apple orchards

The effects of field aging (0–28 days) and pheromone loading rate on the longevity of red rubber septa loaded with the sex pheromone blend of the oriental fruit mothGrapholita molesta (Busck), were evaluated in North Carolina apple orchards in 2002. Separate field tests examined the influence of trap height and pheromone loading rate of rubber septa on trap catches of adultG. molesta males in an abandoned orchard. The loss of the major pheromone component, (Z)-8-dodecenyl acetate (Z8–12:OAc), from red rubber septa over a 4-week period exhibited a relatively constant release rate with 30, 100 and 300 μg pheromone. Trap catch was significantly higher in pheromone traps placed in the upper canopy than in those in the lower canopy. Pheromone traps baited with 100μg lures caught more moths compared with those loaded with 300 μg. There was no apparent relationship between pheromone trap catch and septa age, with trap catch appearing to be primarily a function ofG. molesta population density. http://www.phytoparasitica.org posting May 14, 2006.     

Developing Pheromone Traps and Lures for Maruca vitrata in Taiwan

The larvae of the legume pod borer, Maruca vitrata (Lepidoptera: Pyralidae), cause severe damage on economically important legume crops in the tropics. The female moth produces volatile components to attract males for mating. The so-called sex pheromones are species-specific multi-component blends and are used as lures in crop protection for pest monitoring. Their chemical identification and ratios is critical to design efficient lures. The following sex pheromone components for M. vitrata have been described: (E, E)-10,12-hexadecadienal (major compound), (E, E)-10,12-hexadecadienol and (E)-10-hexadecenal (minor components). The ratio of 100:5:5 of these components was the most attractive in trapping experiments in Benin, Africa. According to this ratio, a synthetic pheromone lure was developed for commercial use. But the commercially available blend was not attractive in field trapping experiments in other regions of sub-Saharan Africa and Southeast Asia. These findings lead to the conclusion that there is a possible polymorphism in the blend composition of the M. vitrata sex pheromone among populations from different geographical regions. In Taiwan, M. vitrata moths were never caught efficiently by the commercially available pheromone lures and traps. This paper reports trap and lure optimization experiments for effective trapping of Taiwanese M. vitrata moths in different leguminous crops.     

Phenology and damage of Anarsia lineatella Zell. (Lepidoptera: Gelechiidae) in peach,apricot and nectarine orchards under semi-arid conditions

This study was conducted under semi-arid conditions in ?anl?urfa province (Turkey) in 2010–2011. One orchard each of peach, apricot and nectarine was selected for the study. There was less than one mile distance separating the orchards, and therefore climate, soil and topography were similar. Adult emergence, population peaks, number of generations per year and damage of the peach twig borer [PTB] [Anarsia lineatella Zell. (Lepidoptera: Gelechiidae)] on twigs and fruits were determined. Sex pheromone traps were used to determine moth population dynamics. Fruits and twigs were checked to determine damage rate and host preference of the PTB among peach, apricot and nectarine. This study showed that the first adults of the PTB were detected in early May and pest populations peaked four times during both years. The highest numbers of adults captured by the pheromone traps in peach, apricot and nectarine orchards were 115, 86 and 70 adults/trap, respectively. The PTB damage rates on twigs were 38, 18 and 16% (2010) (P < 0.05) and 30, 22 and 14% (2011) (P < 0.05), while damage rates on fruits were 29, 6 and 6% (2010) (P < 0.05) and 14, 8 and 5% (2011) (P < 0.05) in peach, nectarine and apricot, respectively. The results showed that A. lineatella caused greater damage on peaches than on apricots and nectarines.     

Effect of avermectin B1 on the development and fecundity of the california red scale,Aonidiella auranth,and on two of its natural enemies:Chilocorus bipustulatus andAphytis holoxanthus

Various immature stages of male and female California red scale,Aonidiella aurantii (Maskell) (Homoptera: Diaspididae), were treated with avermectin B₁ (MK-936) at concentrations ranging from 10 to 100 ppm. Treatments at 10 ppm completely arrested crawler development and 20 and 100 ppm caused 100% mortality of 48-h and 7-day-old male and female 1st instar nymphs, respectively. The development of the 2nd instar was slightly affected by MK-936 at up to 40 ppm. Sublethal doses of the chemical applied to immature stages caused no dramatic reduction in the fecundity of the subsequent, mature females. MK-936 applied to male prepupal and pupal stages and mated females did not prevent male emergence, nor did it affect the ability of males to copulate and inseminate female scales, or the female fecundity. The development and adult emergence of treatedAphytis holoxanthus DeBach (Hymenoptera: Aphelinidae) larvae and pupae parasitizingChrysomphalus aonidum L. scales were not influenced by a 9 ppm MK-936 treatment; leaves sprayed with this concentration had residual toxicity onA. holoxanthus adults for only 24 h post-treatment. Feeding byChilocorus bipustulatus L. (Coleoptera: Coc-cinellidae) on 0.9 ppm MK-936-treated Florida red scales resulted in 100% mortality of 2nd instars and induced sterility in the females.     

Cover Image,Volume 75, Issue 12

The cover image is based on the Original Article The influence of steric configuration of phenazine‐1‐carboxylic acid‐amino acid conjugates on fungicidal activity and systemicity by Xiang Zhu et al., https://doi.org/10.1002/ps.5455 .

     

Sex attractant for the honeydew moth,Cryptoblabes gnidiella

A mixture of (Z)-11-hexadecenal (Z11–16: Ald), (E)-11-hexadecenal (E11–16: Ald), (Z)-13-octadecenal (Z13–18: Ald), and (E)-13-octadecenal (E13–18: Ald) on rubber septa (100∶10∶100∶10 μg, respectively) was superior to virgin females in attracting maleCryptoblabes gnidiella Mill. (Lepidoptera: Pyralidae) to traps. A dichloromethane extract of 200 female ovipositors was separated into fractions by gas-liquid chromatography (GLC) on OV-101 and Hi-Eff 8BP. Two fractions had significant electroantennogram (EAG) activity, and had the retention times ofZ11–16∶Ald andZ13–18∶Ald on each GLC column. These fractions contained insufficient material for further chemical work. SyntheticZ11–16∶Ald andZ13–18∶Ald had the greatest EAG activity of a series of monounsaturated 12?, 14?, 16?, and 18-carbon alcohols, acetates, and aldehydes. Various ratios ofZ11–16∶Ald andZ13–18∶Ald were tested in traps, and a 1∶1 mixture was the most attractive. Addition of small amounts of the correspondingE isomers significantly increased trap catches.     

Detection and estimation of Citrus Tristeza Virus infection rates based on Elisa Assays of packing house fruit samples

Enzyme-linked immunosorbent assay (ELISA) proved to be a sensitive detector for citrus tristeza virus (CTV) in orange fruits (Citrus sinensis (L.) Osbeck). Samples of five fruits were taken from 350-kg packing house containers and tested by ELISA to predict the infection rate of CTV in two infected orange groves. The predicted infection rates, 1% and 11%, were in reasonable agreement with the observed rates of 1% (15/1400) and 16% (324/2053), respectively. The 360 test samples from reputedly uninfected groves all tested negative. These results suggest that the ELISA procedure may provide a general method of detecting viral or other systemic pathogenic infections using the fruit as the test material in place of tree tissue. Fruit samples can be collected routinely at the packing house to reduce test costs.     

Response ofSpodoptera littoralis (Boisd.) andEarias insulana (Boisd.) larvae to azadirachtin and salannin

The effect of azadirachtin and salannin, two triterpenoids isolated from seeds of neem (Azadirachta indica A. Juss), on the feeding response ofSpodoptera littoralis (Boisd.) andEarias insulana (Boisd.) larvae, was investigated. Styropor (foamed polystyrene) lamellae were painted on both sides with a mixture of 5% sucrose with different concentrations of either azadirachtin or salannin dissoled in methanol-water (3∶7). Azadirachtin strongly suppressed feeding inS. littoralis larvae even at 0.001%, whereas salannin showed some antifeedant activity at 0.005% and above. Larvae ofE. insulana were deterred from feeding on azadirachtin-treated lamellae even at 0.005%, whereas salannin was effective only at 0.01% and above. Azadirachtin applied on cotton leaves deterred larvae ofS. littoralis from feeding at all concentrations ranging between 0.001 and 0.02%.     

Alien scale insects (Hemiptera Coccoidea) in European and Mediterranean countries: the fate of new and old introductions

This contribution focuses on recent interceptions and introductions of alien scale insects and their current distribution in European and Mediterranean countries. Data and collections were gathered in markets, nurseries, and botanical gardens, mostly in Italy, either indoors or outdoors. New or recent records of the following alien species are presented: Exallomochlus hispidus (Morrison); Ferrisia virgata (Cockerell) (Pseudococcidae); Coccus viridis (Green); Milviscutulus mangiferae (Green) (Coccidae); Aonidiella orientalis (Newstead); Aspidiotus destructor Signoret; Aulacaspis tubercularis Newstead; Fiorinia fioriniae Targioni Tozzetti; Lepidosaphes pinnaeformis (Bouché); Pseudaulacaspis brimblecombei Williams (Diaspididae). New data and pest status of Phoenicococcus marlatti Cockerell (Phoenicococcidae) and Trabutina mannipara (Hemprich & Ehrenberg) (Pseudococcidae) are also reported. The possible repeated introductions of the latter from North Africa to south Italy by trans-Mediterranean winds, is hypothesized.     

Residue analysis of butocarboxim and aldicarb applied in a drip-irrigated peach grove by the HPLC post-column fluorogenic labeling technique

The new high-performance liquid chromatography (HPLC) post-column fluorogenic labeling technique was used for the analysis of residues of butocarboxim, aldicarb and their sulfoxide and sulfone metabolites in peach leaves and fruits. In order to simplify the procedure, the different metabolites were separated by column chromatography during the cleanup process and the residues were determined by HPLC employing an aqueous methanol solvent in the isocratic mode. The limit of detection for the two insecticides was 0.1 μg/g in the leaves and 0.02 μg/g in the fruit. Aldicarb (10% granular formulation) and butocarboxim (50% E.C. diluted 1:5 with water) were applied to the soil in a drip-irrigated peach grove, by placement under one dripper on one side of each tree. The insecticides were taken up by the tree and distributed almost equally on both sides of the tree. The concentration of the insecticides was somewhat lower in the younger leaves. Residue levels of 0.4 to 0.9 μg/g were detected in the fruits at harvest, 10 and 18 days after the last treatment. Based on the results from the field experiment it was concluded that one of the advantages of drip irrigation was that it enabled adequate control of the green leafhopper (Asymmetrasca decedens) throughout the summer with relatively low dosages of systemic insecticides.