Effects of spinosad and spinetoram on larval mortality,adult emergence,progeny production and mating in Cadra cautella (Walk.) (Lepidoptera: Pyralidae)

The bacterial formulations, spinosad and spinetoram, were evaluated for their efficacy in suppressing development and mating success in Cadra cautella (Walk.) (Lepidoptera: Pyralidae), the almond moth. A dilution series of spinosad and spinetoram was sprayed on rice flour. Rice flour samples sprayed with water served as the control. Late instar C. cautella larvae were introduced onto spinosad-, spinetoram-, or water-treated rice flour. The first experiment tested the effects of spinosad and spinetoram on larval mortality, as well as emergence of adults and progeny at different insecticide concentrations. In the second experiment, the mating success of C. cautella adults that had emerged from larvae exposed to spinosad was tested inside a cubicle. Both spinosad and spinetoram increased larval mortality, whereas both compounds reduced adult emergence and progeny production. Natural mating was reduced in the presence of the synthetic sex pheromone (Z,E)-9,12-tetradecadienyl acetate. However, exposure of C. cautella larvae to spinosad did not alter mating in adult progeny. Spinosad was more effective than spinetoram at suppressing C. cautella development. The study concludes that both spinosad and spinetoram suppress the development of immatures of C. cautella to the adult stage as well as mating. Thus, the both compounds can be used to protect stored grains from infestation by C. cautella.     

Alpha-amylase inhibitor from local common bean selection: Effect on growth and development of Corcyra cephalonica

Cultivars of common bean (Phaseolus vulgaris L.) from the Kalpa valley of the Kinnaur district were screened for alpha-amylase inhibitor activity against porcine pancreatic α-amylase and significant differences were found amongst them. The inhibitor protein was partially purified from Triloki cultivar by ammonium sulphate precipitation and Sephadex G-100 gel filtration chromatography. Inhibitor protein was non-competitive, heat labile and retained 55.51 per cent activity at 70 °C. It had two pH optima of 5.0 and 7.6. Inhibitor protein inhibited amylases of 3rd -4th instar larval extracts of Corcyra cephalonica Stainton, the rice moth. C. cephalonica larvae (3rd -4th instar) were fed on wheat flour mixed with 0.013 percent (w/w) of partially purified α-amylase inhibitor protein. The growth of larvae in the treatment was significantly reduced. Treated larvae showed 100 percent mortality after 11 days. In the untreated control, no larval mortality was observed and adults emerged after 45 days. The inhibitor protein was effective at very low concentrations and could be exploited for control of this grain storage pest.     

The effect of modified atmospheres,an alternative to methyl bromide,on the susceptibility of immature stages of angoumois grain moth Sitotroga cerealella (Olivier) (Lepidoptera: Gelechiidae)

The angoumois grain moth, Sitotroga cerealella is recognized as a common pest of grains world-wide. This investigation aimed at determining the most effective CO₂ concentration in air against the immature stages of the pest in laboratory tests. The sensitivity of newly-laid eggs (<24 h old), 4th instar larvae and 3-day-old pupae to 4 modified atmospheres (MAs) containing 30%, 45%, 65% and 75% CO₂ in air was investigated at 27 °C and exposure periods between 2 h and 264 h. The percentage mortality of the newly-laid eggs, as well as the reduction of adult emergence from 4th instar larvae and 3-day-old pupae tended to increase with the increase of CO₂ concentrations in air and exposure period. According to LT₉₅ values, the order of sensitivity of the three developmental stages of S. cerealella to the four MAs tested was as follows: eggs > pupae > larvae.     

Yield,development, and weight of Cadra cautella (Walker) and Plodia interpunctella (Hübner) on twenty-one diets derived from natural products

Both Cadra (Ephestia) cautella (Walker) and Plodia interpunctella (Hübner) produced more adult progeny, developed faster, and weighed more when reared in a standard moth medium than in any other of 21 natural product diets. Whole cereals and whole soybeans were poor diets, it being assumed that the hard seed coats prevented the larvae from penetrating to the food. Cracked and ground foods were generally more favorable for growth and development and for production of adult progeny. However, ground peanuts caused the death of the seeding adults and offspring of P. interpunctella and also were very unfavorable for C. cautella.     

Susceptibility of different life stages of Indian meal moth Plodia interpunctella (Hübner) and almond moth Ephestia cautella (Walker) (Lepidoptera: Pyralidae) to modified atmospheres enriched with carbon dioxide

The susceptibility of the different life stages of the Indian meal moth Plodia interpunctella and almond moth Ephestia (Cadra) cautella to different modified atmospheres (MAs) containing various concentrations of carbon dioxide (CO₂) was studied as an alternative to methyl bromide fumigation at 27 °C and 60 ± 5% relative humidity (r.h.). The MAs tested were 40%, 60% and 80% CO₂ in air at different exposure times. Results showed that five days were adequate to kill all eggs and pupae of the two moths under all tested MAs. Exposure time needed to be extended to 6 and 7 days at 80% CO₂ to obtain complete mortality of larva of E. cautella and P. interpunctella, respectively. The order of sensitivity of P. interpunctella to MAs was: egg = pupa > larva, while for E. cautella it was: pupa > egg > larva. Generally, eggs and pupae of P. interpunctella were more sensitive to MAs than those of E. cautella but the larvae of the latter were more sensitive.     

Development of resistance in stored grain pest,Trogoderma granarium (Everts) against deltamethrin and its effective control by synergistic toxicity of bifenthrin and chlorpyrifos

The current investigation was conducted to estimate the resistance level against deltamethrin in fourth and sixth instar larvae of Trogoderma granarium collected from wheat storage warehouses of Dera Ghazi Khan (DGK), Okara (OKR) and Gujranwala (GUW). Results showed that the fourth and sixth instar larvae of collected strains warehouses moderately resistant to deltamethrin compared with the same developmental stages of insecticide susceptible laboratory strain (LAB-S). Efficacies of bifenthrin, chlorpyrifos and their various combinations were analyzed against fourth and sixth instar larvae of different strains of pest populations to minimize the development of resistance against deltamethrin. LC_50s of bifenthrin against fourth and sixth instar larvae of all the four populations were recorded at low concentrations compared to deltamethrin. The LC₅₀ values of bifenthrin against fourth instar larvae of LAB-S, DGK, OKR and GUW populations were 359.32, 416.58, 524.01 and 598.91 ppm, respectively, while these values were 204.30, 262.98, 301.89 and 355.22 ppm against sixth instar larvae of those populations, respectively. Chlorpyrifos was found to be the most effective insecticide compared to bifenthrin and deltamethrin. The LC₅₀ values of chlorpyrifos were 189.33, 305.37, 376.30 and 459.15 ppm against fourth instar larvae of LAB-S, DGK, OKR and GUW populations, respectively, whereas for sixth instar larvae those values were 98.24, 129.61, 163.43 and 230.74 ppm, respectively. Various combinations of bifenthrin and chlorpyrifos viz., 1:1, 2:1, 3:1, 1:2 and 1:3 were also tested. Based on the values of LC₅₀ and relative toxic unit, 1:3 combination was observed as the most effective among all combinations. The LC₅₀ values of fourth instar larvae of all the four populations against each insecticide and their combinations were recorded at high concentration compared to that of sixth instar larvae. Results of current investigation need to be considered in present stored grain insect pest control program of warehouses in Punjab¹.     

The lethal effects of three insect juvenile hormone analogues on the developmental stages of Ephestia cautella (Wlk.) (Lepidoptera: Phycitidae)

The juvenile hormone analogue methoprene (ZR 515) was found to interfere with normal development of Ephestia cautella in a manner dependent on dose and age. This compound was found to cause the formation of non-viable 1st instar larvae when it was given to young eggs prior to the stage of blastokinesis, but it was less effective against older eggs. Methoprene inhibited metamorphosis and produced supernumerary giant larvae when it was given to larvae 5 days prior to pupation or younger. However, when given 1–3 days before pupation, it did not prevent pupation but did prevent adult emergence. Young pupae within 1 day of pupation were also found to be very sensitive to the compound. It appears that a small ecdysteroid peak detected 5 days prior to pupation might be responsible for the transition from inhibition of pupation to defective metamorphosis. Methoprene (ZR 515) and hydroprene (ZR 512) were more effective in prolonging the larval period than kinoprene (ZR 777), which, however, was the most effective against Ephestia larvae.     

Investigation on endosymbionts of Mediterranean flour moth gut and studying their role in physiology and biology

The bacterial flora of flour moth and their role in the physiology of Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) were investigated. The gut flora of E. kuehniella was isolated on Luria Bertani Agar (LBA), followed by incubation at 28 °C respectively for 48–72 h. The isolates were identified using 16S rRNA sequencing. Altogether five bacterial species of different genera were identified as Bacillus infantis, Streptomyces cacaoi, Janibacter sp., Stenotrophomonas sp. and Acinetobacter sp. The fourth instar larvae reared on artificial diet without any antibiotic showed higher efficiency of conversion of digested food (ECD) and efficiency of conversion of ingested food (ECI) (16.068 ± 0.568% and 14.455 ± 0.448%), respectively. Approximate digestibility (AD) and Consumption index (CI) of the fourth instars larvae were higher on artificial diets containing tetracycline. The higher activity of alpha-amylase and general proteases were observed in the midgut of larvae reared on artificial diet containing antibiotic chloramphenicol. Total protein and lipid value were higher respectively in larvae that were reared on artificial diet containing streptomycin sulfate and artificial diet containing tetracycline. It seems that antibiotics had no significant effect on enzymatic activities of E. kuehniella. The larvae performed well in tetracycline treatment as per larval developmental duration compared with other treatments. Therefore, the gut bacteria do not seem to play a crucial role in the survival and development of the E. kuehniella. However, the question of adaptation of this pest species to hosts rich in protease inhibitors, such as flour has to be examined and ascertained.     

Potential of four Turkish isolates of entomopathogenic nematodes against three major stored products insect pests

The insecticidal effect of native entomopathogenic nematode (EPN) isolates (Steinernema feltiae UTP-5 isolate, Heterorhabditis bacteriophora UMK-7 isolate, S. feltiae DDKY-11 isolate and H. bacteriophora AVB-15 isolate) recovered from the Cappadocia Region of Turkey were investigated on the adults of S. granarius and R. dominica and the larvae of E. kuehniella at different temperatures (15 °C, 20 °C and 25 °C) and concentrations (250, 500 and 1000 IJs/adult for S. granarius and R. dominica; 10, 50 and 100 IJs/larvae for E. kuehniella) under controlled conditions. Insect mortality was recorded after 4th, 6th and 8th day of exposure time for S. granarius and R. dominica, and 2nd and 4th day for E. kuehniella. The results showed that the efficacy of the isolates at 25 °C was generally higher than the ones at 15 °C and 20 °C. Steinernema feltiae DDKB-17 isolate caused the highest mortality (86%) against S. granarius adults at all temperatures tested. The virulence of the tested isolates on R. dominica adults did not exceed 44% at all temperatures and concentrations tested. UMK-7 and AVB-15 isolates were the most virulent isolates against E. kuehniella larvae with a mortality rate of 100%. Based on the results obtained from the laboratory tests, it appeared that the isolates tested have a good potential for the management of S. granarius, R. dominica and E. kuehniella.     

The effects of a previous field infestation upon Ephestia cautella (Walker) and Lasioderma serricorne (F.) infesting carobs

In laboratory trials, larvae of Ephestia cautella (Walker) successfully developed upon sections of the pods of the carob tree (Ceratonia siliqua L.) which had previously been infested in the field by Ectomyelois ceratoniae (Zeller), but failed almost completely to develop upon sections of the pods which had not been infested in the field. Significantly more eggs were laid by Ephestia cautella adults on previously infested carob than on previously uninfested carob, and when newly-hatched Ephestia cautella larvae were given a choice between previously infested carob and previously uninfested carob, significantly more of them selected the previously infested carob.Larvae of Lasioderma serricorne (F.) developed successfully on both previously infested carob and previously uninfested carob, and neither adult nor larval Lasioderma serricorne could be shown to discriminate between previously infested and undamaged carob.     

Lethal effects of sulfuryl fluoride on eggs of different ages and other life stages of the warehouse moth Ephestia elutella (Hübner)

Sulfuryl fluoride (SF) is a fumigant used for the control of stored-product pest insects and is a feasible alternative to some uses of methyl bromide. SF was first registered in Germany in 2004 for disinfestation of emptied flourmills, emptied food storages and dried fruit. One- to 4-day-old eggs, larvae and pupae of the warehouse moth, Ephestia elutella (Hübner) (Lepidoptera) were investigated for their susceptibility to SF under different conditions. Each life stage was exposed for 18 h, 24 h or 48 h, to 11.6 g/m³ or 21.3 g/m³ at 15 °C, 20 °C or 25 °C and 65% relative humidity. A Fourier transform infrared (FTIR) spectrometer was used to determine the concentrations of SF. Within 18 h of exposure, all larvae and pupae of E. elutella died at 11.6 g/m³ at all three temperatures. The 1 and 2- day-old eggs were generally more susceptible, whereas the 3 and 4-day-old eggs were more tolerant to the SF treatment. All eggs of all ages were controlled within 48 h of exposure to the concentration of 21.3 ± 1.3 g/m³ at temperatures of 20 °C and 25 °C.     

The separation of live stored product insect larvae from flour or sievings using a modified Tullgren funnel

A modified commercially available Tullgren funnel was used to separate live, early or late instar larvae from 200 g (2·5 cm deep) and 400 g (5·0 cm deep) samples of wheat flour or kibbled maize. Larvae were extracted more readily from 200 g even though temperatures were lower after 24 hr than in the larger samples.Although only 26 per cent of early instar larvae of Tribolium castaneum were recovered from 400 g samples of wheat flour in 24 hr, all other trials with larvae of this insect yielded 85 per cent recovery or higher. With larvae of Lasioderma serricorne, Trogoderma granarium and Ephestia cautella the recoveries were highest for late instar larvae in 200 g of kibbled maize and lowest from 400 g of wheat flour. Oryzaephilus surinamensis larvae could not be adequately extracted from wheat flour but when non-infested kibbled maize was mixed with it, up to 58 per cent recovery was obtained.It is concluded that the modified Tullgren funnel would provide a useful method for extraction of live insect larvae from samples of finely divided food such as flours or meals.     

Insect infestation of a botanicals warehouse in north-central Florida

The insect populations of a botanicals warehouse in north-central Florida were studied to gain a better understanding of insect problems associated with stored botanicals and to identify measures that could be taken to mitigate the problems. The warehouse contained either dried saw palmetto berries, Serenoa repens (Bartram) Small, or dried passion-flower (maypop) vines, Passiflora incarnata (L.), depending on the season. Insect populations were monitored intermittently for one year using arrays of moth and beetle traps. Capture rate, relative abundance, and spatial distribution of different species were examined over time. The six most abundant species in order of abundance were: Cadra cautella (Walker), Lasioderma serricorne (F.), Oryzaephilus mercator (Fauvel), Typhaea stercorea (L.), Plodia interpunctella (Hübner), and Tribolium castaneum (Herbst). All of these appear capable of infesting saw palmetto, but the major pests were C. cautella and L. serricorne. Oryzaephilus mercator and P. interpunctella were also important, but T. castaneum and T. stercorea were minor. Passion-flower was a less suitable host than saw palmetto for all of the species except T. stercorea. Nevertheless, all of the six species infesting saw palmetto except O. mercator were captured in numbers sufficient to indicate that they were also capable of infesting passion-flower. Lasioderma serricorne was the major pest. Spatial analysis of trap captures revealed that the insect distributions changed as different botanicals were brought in, removed, or redistributed in the storage area. Potential measures to mitigate insect problems in stored botanicals are discussed, including spatial targeting of insect control and sanitation efforts.     

Inhibition of egg and larval development of the Indian meal moth Plodia interpunctella (Hübner) and almond moth Ephestia cautella (Walker) by gamma radiation in decorticated hazelnuts

In this study, inhibition of egg hatching and development of immature stages of the Indian meal moth and almond moth by irradiation in hazelnuts was investigated. Irradiation doses required to inhibit the development of eggs of Plodia interpunctella and Ephestia cautella were 450 and 300 Gy, respectively, and no adults of either species emerged from treated samples (all stages) at 1 kGy of radiation in large-scale tests. The low-dose irradiation treatment did not cause excessive oxidative deterioration and no significant differences were found in organoleptic studies at 0.5-3 kGy in decorticated hazelnuts. However, total tocopherol content decreased depending on irradiation dose.     

Effects of azadirachtin on post-embryonic development, energy reserves and α-amylase activity of Plodia interpunctella Hübner (Lepidoptera: Pyralidae)

The effects of azadirachtin on the fourth instar larvae of Plodia interpunctella (Lepidoptera) were investigated. When incorporated into the diet at 2 and 4 ppm, azadirachtin provoked larval weight loss, developmental delay and high larval and pupal mortality. Spectrophotometric assays showed that azadirachtin caused a severe reduction in protein, glycogen and lipid contents 7 days after the beginning of the treatment. In addition, α-amylase activity was reduced in larvaefed azadirachtin.     

Maize hybrids affected nutritional physiology of the khapra beetle,Trogoderma granarium Everts (Coleoptera: Dermestidae)

The Khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae), is an important insect pest of stored cereals, grains and other stored products in Iran and some countries of the world. Nutritional indices and digestive enzymatic activity of fifth instar T. granarium were investigated on nine maize hybrids (704, AR 89, AS 71, AS 77, BC 678, KSC 703, PL 472, SC 704, and Simax) at 33 ± 1 °C, relative humidity of 65 ± 5%, and a photoperiod of 14: 10 (L: D) h. The highest and lowest food consumption by larvae was on AR 89 and BC 678, respectively. Fifth instar larvae fed on 704 had the highest efficiency of conversion of ingested food, and those fed on BC 678 showed the lowest relative growth rate. The larval growth index, standardized insect-growth index and fitness index were the highest when larvae were reared on PL 472, and the lowest when they were reared on BC 678. The highest proteolytic and amylolytic activity was on KSC 703, and the lowest activity was on BC 678. The results of this study indicated that BC 678 was an unsuitable hybrid for feeding of fifth instar T. granarium. Studying the nutritional physiology of T. granarium on different maize hybrids can be useful in identifying the anti digestive compounds of host grains, which can be expressed in genetically engineered crops to confer resistance to this key pest.     

Assessment of eight rice cultivars flour for feeding resistance to Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae)

Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) is an important pest of processed stored grains worldwide. Study of life history, feeding efficiency and digestive function of an insect on different host cultivars can indicate their resistance for the insect's population increase. Due to the economic importance of T. castaneum on stored rice flour, this research was aimed to investigate the life history, feeding indices and digestive enzymatic activity of T. castaneum on flour of eight rice cultivars (Ali-Kazemi, Dom-Siah, Fajr, Gilaneh, Gohar, Hashemi, Khazar, and Neda). A delay in the developmental time of T. castaneum was detected on cultivar Gohar. The lowest fecundity and egg fertility were observed on cultivar Gohar. Feeding indices of fourth instar larvae were the lowest on cultivars Gohar and Neda. The amylolytic activity of fourth instar larvae was the highest on cultivars Hashemi, Dom-Siah, Ali-Kazemi and Gilaneh, and the lowest on cultivar Gohar. Also, the highest and lowest proteolytic activities of fourth instar larvae were on cultivars Khazar and Hashemi, respectively. Significant correlations were detected between tested parameters of T. castaneum with starch and protein value of examined cultivars flour. The results of cluster analysis indicate that Dom-Siah, Hashemi and Ali-Kazemi are relatively susceptible cultivars, and other tested cultivars, especially Gohar, are relatively resistant cultivars for feeding of T. castaneum. The resistant rice cultivars could be further evaluated to identify secondary biochemicals that contribute to T. castaneum resistance.     

Suppression of laboratory populations of Ephestia cautella (Walker) (Lepidoptera: Pyralidae) by release of males with cytoplasmic incompatibility

Unidirectional cytoplasmically incompatible males of Ephestia cautella (Walker) were substituted for irradiation-sterilized males in a modification of the sterile-male release technique. Laboratory populations were greatly suppressed or eliminated by single releases of incompatible males at ratios of 14:1 or greater. Isolated populations in nature (i.e., within a closed warehouse) could probably be eliminated by using this technique, but release ratios as high as 100:1 might be necessary.     

Diapause in twenty populations of Ephestia cautella (Walker) (Lepidoptera: Pyralidae) from different parts of the world

Population samples of Ephestia cautella from difierent parts of the world were examined under various conditions of temperature and photoperiod for the incidence of diapause. In all but one of the twenty samples, larvae wandered for extended periods in search of sites to pupate, and diapause lasted over 50 days in some individuals from fifteen samples at 20°C, including five from the tropics. Some larvae of all fifteen samples diapaused in constant darkness but larvae from only eight, including just one from the tropics, diapaused in short photoperiods, and from only five of these, in constant light. Only one population, that in which diapause had previously been reported, diapaused at 25°C. Except in samples of this and three other populations, the proportion of larvae entering diapause did not exceed 50% under any of the conditions tested.The duration of diapause was in general quite short, mean times to pupation ranging from about 4–15 weeks. At 20°C, individuals from seven populations diapaused for longer than 12 weeks, and only a very few from three populations diapaused for over 20 weeks. Diapause is thus unlikely to enable E. cautella to overwinter in the UK in unheated premises.     

Insecticidal effect of Steinernema feltiae (Filipjev) (Nematoda: Steinernematidae) against Tribolium confusum du Val (Coleoptera: Tenebrionidae) and Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) in stored wheat

The confused flour beetle, Tribolium confusum, and the Mediterranean flour moth, Ephestia kuehniella, are important pests of stored grain products. The insecticidal effect of three strains (UK 76 [=Nemasys], USA/SC, and Hawaii) of the entomopathogenic nematode Steinernema feltiae was determined in the laboratory, in wheat, against these pests. The nematodes were applied at three dose rates: 100, 300 and 900 nematodes/insect individual. The Hawaii strain was most virulent against T. confusum adults and larvae, with a significant dose effect in the case of the larvae. Larval mortality of this species reached 79% and 100% after 7 and 14 d of exposure to the nematodes, respectively, at the highest dose applied. On the other hand, adult mortality of T. confusum did not exceed 66%. In the case of E. kuehniella larvae, USA/SC performed best causing 52% and 69% mortality after 7 and 14 d exposure, respectively, at the highest dose tested. Since very few data are available on the effect of entomopathogenic nematodes against these pests, it is concluded that the Hawaii and USA/SC strains of S. feltiae should be further investigated as promising biological control agents for T. confusum and E. kuehniella.