The use of traps baited with live females or synthetic pheromone as a tool for improving control programs of the cotton leaf-worm,Spodoptera littoralis (Boisd.), in cotton fields in israel

The aim of this investigation was to clarify whether pheromone traps could provide a reliable tool for early detection of aS. littoralis adult population and for indicating infestation by its larvae in the field. The aggregated pattern of distribution of adults is indicated by the fit of data to Taylor’s Power Law or to the negative binomial distribution. However, the relatively high k values obtained indicate thatS. littoralis adults are only slightly aggregated and sometimes almost randomly distributed. Trap position in the field and number of traps per area unit affected size of catches in both female-baited and synthetic-pheromone-baited traps. No relationship between size of catches and temperature, wind velocity or moon phase was detected. Variations in size of catches among traps was not affected much by the baited females. Pheromone traps proved to be a reliable tool for estimating fluctuations in population density and for indicating adult peaks. However, no correlation between male catches and infestation by larvae in the experimental plots was found. Pheromone traps may serve only as a warning device indicating the possibility of potential attack due to an increase in adult population level. Mercury vapor light traps were inferior to pheromone traps in detecting changes inS. littoralis population densities. Synthetic pheromone (“Litlure”) was somewhat less efficient in attracting males than virgin females; however, it is suitable for detecting fluctuations in theS. littoralis adult population.     

Sex ratio and mating status ofSpodoptera Littoralis females collected from light traps in Israel

Spodoptera littoralis moths were collected from two mercury vapor light traps in Israel, sexed, and the females dissected to establish the number of times each had mated. The sex ratio was in favor of males. The higher the percentage of males in the trap, the higher was the corresponding percentage of mated females and number of matings per female. MostS. littoralis females mated more than once. The mating status varied with location and season.     

Efficiency of the synthetic sex attractant and the effect of trap size on captures ofSpodoptera littoralis males in water traps and in dry funnel traps

The efficiency of the synthetic sex attractant ofS. littoralis and the effect of trap size on male captures in water traps and in newly designed dry traps were investigated. The synthetic attractant was less efficient in attractiveness than virgin females in both small (17 cm) and large (60 cm) traps. Trap size did not affect male captures in traps baited with either virgin females or synthetic pheromone. The dry trap tested was as efficient as the water trap, easier to handle, and highly suitable for monitoring or for mass trapping ofS. littoralis.     

The Use of Sex Pheromones in the Control of Spodoptera littoralis Boisd.1)

An even network of pheromone traps baited with virgin females of Spodoptera littoralis Boisd. was established in Cyprus. By relating trap catches with meteorology it was shown that no major immigration of S. littoralis to Cyprus from surrounding land-masses had occurred. Direct control of S. littoralis by the synthetic pheromones recently synthesized or the sterile male technique may therefore be possible in such an area of ecological isolation.     

A modified dry pheromone trap forSpodoptera Littoralis male moths

A new technique was employed to catchSpodoptera littoralis males, based on coating the polyethylene funnel of a pheromone trap with kaolin. This trap doubled the number of males trapped and increased the fraction of live moths per catch by 20%, compared with an uncoated-funnel trap. At an angle of 60°, males fell off a polyethylene sheet coated with kaolin or talcum, whereas they remained adhered to an uncoated sheet even at 90°. Scanning electron microscope observations showed that leg parts in contact with the kaolin coat are contaminated with free kaolin, which causes the moths to lose contact with the coat and to fall into the trap, whereas without the kaolin coat moths could adhere to the polyethylene. Practical uses of the technique in field traps are discussed.     

Captures ofEarias insulana males in water traps and dry funnel traps baited with synthetic pheromone or virgin females

(E, E)-10,12-hexadecadienal (HDD) effectively attracted males ofEarias insulana (Boisduval) when released from polyethylene vials but not from rubber dispensers. Traps baited with 3 mg HDD/trap were as effective in luring males as traps baited with four virgin females. Funnel traps baited with either HDD or virgin females captured significantly more males than water traps baited with the same lures.     

Mating,longevity, fertility and fecundity of the cotton leaf-worm,Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae)

The mechanisms adopted to ensure mating success, fertility and fecundity ofS. littoralis were studied. The male moths usually mate only once a night but they mate repeatedly during most of their life span, and practically all their spermatophores are equally efficient for inseminating a female. Although females are also multiple maters, one spermatophore is sufficient for a female to lay fertile eggs throughout her life with no reduction in potential fecundity. While a male may mate 5.3 times, on the average, a female may mate only 2.3 times. As a pronounced decrease in pheromone release occurs after mating, a repeat mating by a female will occur only after most neighboring competitive virgin females have been inseminated. A male may mate therefore with 5.3 different females, all of which will be thoroughly inseminated. The female moth is ready to mate just after emergence and at any time throughout her life. If mating is delayed the preoviposition period is greatly prolonged and eggs are saved to be laid later, after mating, as fertile eggs. Delay in egg laying due to delayed insemination does not result in reduced fecundity as it is compensated for by prolonged longevity. Even if mating is greatly delayed and occurs after egg laying has already begun, the potential reduction in reproduction is not very great, due to the low daily egg-laying rate and the increased longevity of unmated females. It appears unreasonable to expect any tendency toward reduction of egg production with a decrease in the ratio of adult males in a population; for this purpose the control of males must be essentially complete. Therefore, a behavioral control program by mass trapping ofS. littoralis males is unlikely to be economically feasible.     

The Effects of Atrazine in Maize-Wheat Rotations

Abstract

Catches of male moths of the Egyptian cotton leafworm, Spodoptera littoralis (Boisd.), in light traps and pheromone traps were compared at an experimental site at Sakha (Kafr El-Sheikh Province, Egypt) between June and November 1976. The catches in the pheromone traps were generally higher than those in the light traps, although the difference ratio varied from month to month. It was concluded that pheromone traps provided a useful ecological tool for S. littoralis in Egypt.     

Regional differences in pheromone responses of diamondback moth in Indonesia

Trap captures with two‐ and three‐component blends of synthetic sex pheromone for the diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae), were assessed in Indonesia. In West Java, the two‐component blend containing 10g of (Z)‐11‐hexadecen‐1‐ol acetate and (Z)‐11‐hexadecena| in a 4:6 ratio captured the greatest number of diamondback moths. Three and five virgin females were more attractive than the two‐component lures, which were as attractive as lures that also contained (Z)‐9‐tetradecen‐1‐ol acetate. In North Sulawesi, a 100 g dose of the two‐component blend attracted more males than the 10 g dose but was not significantly more potent than five virgin females. These results suggests that pheromone production and bioactivity should be assessed in separate populations prior to attempts to develop pheromone‐based monitoring or mating disruption programmes.     

Captures of markedspodoptera littoralis (boisd.) male moths in virgin female traps: Effects of wild male population,distance of traps from release point,and wind

Field experiments were conducted to clarify the effective sphere of pheromone traps for capturingS. littoralis males. Most males were recaptured on the night of release and only a few were trapped on the following night. Recapture of males was not affected by the number of wild males present in the field. Percent recapture was negatively correlated with the distance of traps from the release point, decreasing markedly at distances beyond 100 m. Percent recapture was not affected by wind speeds ranging from <1 to 5 knots per hour, but was affected by wind direction.     

Field evaluation of synthetic sex pheromone traps for the cocoa mirid Sahlbergella singularis (Hemiptera: Miridae)

BACKGROUND: Field trapping experiments were conducted to evaluate the attractiveness of five different pheromone blends as well as the impact of trap design on attractiveness towards cocoa mirids, Sahlbergella singularis Hagl. and Distantiella theobroma (Dist.), in Cameroon. RESULTS: A total of 361 adults of S. singularis (359 males and two females) were caught. The highest numbers of mirids were found in traps with pheromone blends that combined a monoester and a diester, compared with traps with the diester or the monoester individually and control traps with no pheromone. Rectangular traps caught significantly more mirids compared with delta traps. The mean number of 5.1 mirids trap^?1 year^?1 caught in rectangular traps was significantly higher compared with the 1.8 mirids trap^?1 year^?1 for the delta traps. CONCLUSION: The data revealed that rectangular traps containing pheromone blends combining both the monoester and the diester have a good potential to lure and trap adult males of S. singularis on cocoa farms. The pheromone blends used were specific for S. singularis, and the use of pheromone traps appears to be a promising strategy for incorporation into integrated pest management strategies for the monitoring or even the control of S. singularis in cocoa plantations. Copyright © 2011 Society of Chemical Industry     

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.     

Field evaluation of purified Z-9, E-11-tetradecadienyl acetate as an attractant for males ofSpodoptera littoralis (Boisd.) (Lepidoptera,Noctuidae)

The efficiency of 100% purified Z-9, E-11-tetradecadienyl acetate, the major sex attractant for males ofS. littoralis, was evaluated in a field test. A trap (17-cm diameter) baited with 2 mg of the purified attractant dispensed in polyethene vials, was significantly less efficient in attractiveness than a trap baited with one virgin female. The importance of a synergistic component for improving the efficiency of theS. littoralis sex pheromone is discussed.     

苹果蠹蛾不同防治方法的控害效应比较

为了及时地在苹果蠹蛾Cydia pomonella(L.)入侵地实施有效的防控策略,通过评价活雌蛾诱捕器诱捕雄蛾数量、在树干上化蛹或越冬的幼虫数量以及对苹果果实的为害程度,比较性信息素诱杀技术、迷向技术和化学防治技术对苹果蠹蛾的控害效应。结果显示,采用迷向法控制苹果蠹蛾的防治效果与化学防治相当,其中在第1代幼虫为害盛末期,蛀果率可控制在1%以下,在第2代幼虫为害盛末期,可控制在2%左右;而诱捕区与对照区(无处理)的蛀果率相当,几乎无控制效应。     

Effect of height of pheromone trap on the capture ofSpodoptera litura moths in tobacco nurseries

Experiments conducted during 1981/82 and 1983/84 in a tobacco nursery showed that the male moth catch ofSpodoptera litura F. was significantly higher in pheromone traps 2.0 m above ground level, than at lower or higher elevations.     

Control of the pink bollworm <Emphasis Type="Italic">Pectinophora gossypiella</Emphasis> by the mating disruption technique on cotton in a semi-arid region of Turkey

This study evaluated the effectiveness of mating disruption pheromones for the pink bollworm (PBW) Pectinophora gossypiella (Saund.) (Lep.: Gelechiidae) and determined the damage levels of cotton plants in Turkey in 2007 and 2008. Adult populations were monitored by pheromone traps, with 250 pieces ha⁻¹ of PBW rope dispensers used for each treated field of approximately 12 ha. Calculations were based on comparing cotton yield in the control field with that in treated fields. The PB-Rope L dispensers significantly decreased both number of males in the pheromone traps and cotton boll damage. Results showed that PB-Rope L dispenser application during the square period of cotton plants effectively reduced damage. Cotton yield of treated fields was increased compared with control fields by 20.28% and 10.28% in 2007 and 2008, respectively. Infestation ratios were determined by comparing cotton bolls collected from treated fields with bolls from control fields; the results were 25% and 15% for control fields and 16% and 4% for treated fields in 2007 and 2008, respectively. Larval densities in the control fields were higher than those in the treated fields in both years. Results showed that the PB-Rope L dispensers released pheromone satisfactorily to disrupt pest mating.     

Inhibition of pheromone response in Sesamia nonagrioides by the pheromone of the sympatric corn borer, Ostrinia nubilalis

Sesamia nonagrioides Lef. and Ostrinia nubilalis (Hübn.) are two corn borers present in the Mediterranean area that share a similar feeding habitat. The female sex pheromones of the two species consist of (Z)-11-hexadecenyl acetate, (Z)-11-hexadecen-1-ol, (Z)-11-hexadecenal and dodecyl acetate (77:8:10:5 w/w) and (Z)-11-tetradecenyl acetate and (E)-11-tetradecenyl acetate (97:3 w/w) respectively. Although the pheromones share no common components, previous work had shown the inhibition of the response by O. nubilalis males to their own pheromone owing to the presence of S. nonagrioides pheromone. In this study, the pheromone of O. nubilalis and its two components separately were shown to inhibit the attraction of S. nonagrioides males to the synthetic female pheromone in both laboratory wind-tunnel bioassay and field trapping studies. In the wind tunnel, the number of contacts of S. nonagrioides males with the source were significantly (P < 0.05) reduced by the single pheromone components of O. nubilalis. In the field, the addition of 1% of O. nubilalis pheromone significantly (P < 0.05) reduced the catches of S. nonagrioides males. The components of both pheromones also elicited electroantennographic responses from antennae of male S. nonagrioides moths. The ecological consequences and the possibilities of applying this cross-inhibition for mating disruption techniques are discussed.     

Impact of sub-lethal residues of azinphos-methyl on the pheromone-communication systems of insecticide-susceptible and insecticide-resistant obliquebanded leafrollers Choristoneura rosaceana (Lepidoptera: Tortricidae)

The effects of sub-lethal residues of azinphos-methyl on pheromone production, calling, female attractiveness and the ability of males to locate sources of natural and synthetic pheromone were compared in azinphos-methyl-susceptible (susceptible) and azinphos-methyl-resistant (resistant) obliquebanded leafrollers, Choristoneura rosaceana (Harris). The amount of pheromone in susceptible females was reduced by 29-33% after exposure to azinphos-methyl; this treatment did not affect the pheromone content of resistant females. Azinphos-methyl-treated resistant females contained 39-43% less pheromone than azinphos-methyl-treated susceptible females. Resistant females that were not treated with azinphos-methyl contained 35-56% less pheromone than susceptible females that were not treated with insecticide. The incidence of calling was reduced by 67-100% in azinphos-methyl-treated susceptible females; the incidence of calling by resistant females was not affected by exposure to azinphos-methyl. The incidence of calling by azinphos-methyl-treated susceptible females was 58-100% lower than that of azinphos-methyl-treated resistant females. There was no difference in the incidence of calling between susceptible and resistant females that had not been treated with insecticide. In a flight tunnel, treatment with insecticide reduced the attractiveness of susceptible females by 38%; treatment with insecticide did not affect the attractiveness of resistant females. There was no difference in the proportion of males attracted to susceptible and resistant females that had, or had not been treated with insecticide. In an apple orchard, the attractiveness of susceptible and resistant females treated with azinphos-methyl was reduced by 84 and 12%, respectively. The proportion of males attracted to azinphos-methyl-treated susceptible females was 58% lower than the proportion attracted to azinphos-methyl-treated resistant females, whereas, if females were not treated with insecticide, the proportion attracted to resistant females was 57% lower than the proportion attracted to susceptible females. In a flight tunnel, azinphos-methyl did not affect the ability of susceptible or resistant males to locate a source of pheromone gland extract. Likewise, in an apple orchard, the insecticide treatment had no effect on the ability of susceptible or resistant males to locate a source of synthetic pheromone. In a flight tunnel, there was no difference in the proportion of azinphos-methyl-treated susceptible and resistant males locating a source of pheromone gland extract; however, in the orchard, 39% fewer azinphos-methyl-treated resistant males located a source of synthetic pheromone than azinphos-methyl-treated susceptible males. A similar proportion of susceptible and resistant males that had not been treated with insecticide located a source of pheromone gland extract in the flight tunnel, but in the orchard, the proportion of resistant males not treated with azinphos-methyl that located the source of synthetic pheromone was 32% lower than the proportion of susceptible males not treated with this insecticide. The implications of the differences in the effect of sub-lethal residues of azinphos-methyl on the pheromone communication system of susceptible and resistant moths are discussed in relation to the theory of the development of insecticide resistance, the detection of resistance in feral populations of moths using sex pheromone-baited traps, and the control of moths using sex pheromone-mediated mating disruption.     

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.