Flight responses of Sitotroga cerealella (Lepidoptera: Gelechiidae) to corn kernel volatiles in a wind tunnel

The flight behavioral responses of males and females of Sitotroga cerealella (Lepidoptera: Gelechiidae) to corn kernel volatiles, in a wind tunnel, and the determination and identification of the active compounds of corn kernel volatiles were investigated. A wind tunnel bioassay was carried out to test the response of males and females to 15, 30, 60, and 120 g equivalents of corn kernel volatiles. Gas chromatography-electroantennography was used to determine which components in corn kernel volatiles elicited an EAD response using male and female antennae. Gas chromatography-mass spectrometry technique was used to identify the active compounds of corn kernel volatiles. A 60-g equivalent of corn kernel volatiles elicited attractant behavior of unmated males to landing near the source. Mated males and virgin females were not attracted to corn kernel volatiles. The number of mated females landing was significantly higher in 60- and 120-g equivalents of corn kernel volatiles, compared to the other concentrations and the control. The antennae of males and females responded to four active compounds of corn kernel volatiles. Three of these compounds were identified, namely nonanal, decanal, and geranyl acetone. It is suggested that host finding and selection by S. cerealella is associated with its host volatiles.     

Insecticidal activities of garlic substances against adults of grain moth,Sitotroga cerealella (Lepidoptera: Gelechiidae)

Abstract The angoumois grain moth, Sitotroga cerealella (Olivier), is one of the most serious stored grain pests around the world. In attempts to reduce the losses caused by the moth and to suppress its populations, the fumigant activities, behavioral influence and ovipositional inhibition of garlic (Allium sativum) essential oil and its two major components, diallyl disulfide and diallyl trisulfide, were investigated against the adult grain moth. Their effects on reduction in survival of first instar larvae to adult emergence were also evaluated. Results showed that these three materials (garlic essential oil, diallyl disulfide and diallyl trisulfide) had significant fumigant activity with 50% lethal concentration values at 1.33, 0.99, and 1.02 μL/L air space, respectively; meanwhile, the three materials possessed high behavioral deterrent activities against adults in the Y‐tube olfactometer. When applied to rice grains, these materials reduced adult longevity and inhibited oviposition, with ovipositional inhibition above 70% at a concentration of 1.5 μL/25 g in either no‐choice or two‐choice tests. In short, the study showed that both diallyl disulfide and diallyl trisulfide, like garlic essential oil, acted as fumigants, produced behavioral deterrence and inhibited oviposition against angoumois grain moth. Our work here indicates that diallyl disulfide and diallyl trisulfide may serve as potential alternatives for grain protectants since both of them can be prepared easily from readily available chemicals.     

Management of Sitotroga cerealella in stored cereal grains: a review

The economic loss due to pest attack in stored commodities is a serious problem worldwide. About 200 insect species attack stored commodities. These insect pests are responsible for quantitative and qualitative losses in cereal grains. Among the stored grain pests, Angoumois grain moth, Sitotroga cerealella is considered as common, top of the list and most destructive pest of cereal grains. Its infestation starts in the standing crop and continues in storage. Although there are many control strategies, our need is some effective, cheap and readily available strategy for safe storage. This review presents different ways by which S. cerealella can be controlled. In this paper, a list of approaches is given which are used to improve the protection of stored grains against S. cerealella attack. These approaches include use of edible oils, containers, synthetic chemicals, agricultural waste materials, plant derivatives, bacterial protoxins, biopesticides, biocontrol enhancers and semiochemicals. If these tactics are followed as combined strategies in a compatible manner, they can provide us an integrated pest management programme for the efficient control of S. cerealella in cereal grains.     

Biology and thermal requirements of Chrysoperla genanigra (Neuroptera: Chrysopidae) reared on Sitotroga cerealella (Lepidoptera: Gelechiidae) eggs

Chrysoperla genanigra Freitas is a common green lacewing associated with melon pests in the Northeastern Brazil. All life stages of this recently described species were studied under a range of constant temperature conditions (17, 21, 25, 29, 33, 35 and 37 °C), a photoperiod of 12 h:12 h (L:D) and 70 ± 10% relative humidity. Adults of C. genanigra were fed on a diet consisting of a 1:1 (v/v) mixture of brewer’s yeast and honey, while larvae were provided with eggs of Sitotroga cerealella (Olivier) ad libitum. The duration of preimaginal development of the species was inversely proportional to temperature and ranged from approximately 63 days at 17 °C to 15 days at 35 °C. The percentage of adult emergence varied from 6.7% at 17 °C to 76.7% at 25 °C, although no larvae were able to complete development at 37 °C. The lower thermal threshold for total preimaginal development was approximately 10.8 °C and the thermal requirement was 336.7 degree-days. Egg production, along with the longevity of both males and females, were significantly affected by temperature. It is concluded that the best temperature for rearing C. genanigra is 25 °C, with the lowest preimaginal mortality and the highest egg production (992.7 eggs/female).     

Insecticidal efficacy of some plant powders and extracts against the Angoumois grain moth,Sitotroga cerealella (Olivier) (Lepidoptera: Gelechiidae)

Powder and extract from four plants were evaluated for their insecticidal efficacy against the Angoumois grain moth, Sitotroga cerealella (Olivier) in the laboratory at a temperature of 28 ± 2°C and a relative humidity of 75 ± 5%. The plants included Aristolochia ringens L., Khaya ivorensis (K.), Strophanthus hispidus (D.C.) and Zanthoxylum zanthoxyloides Lam. The powder was applied at the rate of 0.2, 0.4 and 0.6 g/20 g of paddy rice, while the extract was applied at the rate of 1%, 2% and 3%/20 g of paddy rice. Parameters evaluated were adult moth mortality, adult emergence and weight loss in treated paddy after infestation. Results shows that adult moth mortality increased as concentration of powder increased. Significant differences (p < 0.05) existed among the plant powders andthe concentration. A 100% mortality rate was obtained within 7 days when A. ringens was applied at 0.4 and 0.6 g/20 g of paddy. S. hispidus was able to effect 100% mortality only at 0.6 g. This shows that A. ringens had the greatest insecticidal activity while the least effective was K. ivorensis. Adult emergence shows that more adult S. cerealella emerged from the control (40.3) which was significantly higher (p < 0.05) than others. Fewer adults emerged from paddy treated with plant powder with the least in A. ringens. Generally, adult emergence reduced with an increase in the concentration of powder. The extract from all the four plants tested against S. cerealella was able to effect 100% mortality of the adult moths within 24 h of application at all concentrations. Significant differences (p < 0.05) existed among all the different plant powders in terms of weight loss. The weight loss in paddy was significantly higher (p < 0.05) in the control (57.7%) than others. Weight loss was least in paddy treated with A. ringens at 0.4g/20 g of paddy with 2.2%. Generally, weight loss decreased with increase in powder concentration. The treatment with the highest adult emergence (control) also had the highest weight loss, while the treatment with the lowest adult emergence (A. ringens) had the lowest weight loss.     

Life table and biological studies of Harmonia axyridis Pallas (Col., Coccinellidae) reared on the grain moth eggs of Sitotroga cerealella Olivier (Lep., Gelechiidae)

The developmental period of immature stages, survival per cent, longevity, fecundity and life table parameters of Harmonia axyridis by feeding on fresh and frozen grain moth eggs (GME) of Sitotroga cerealella were studied under laboratory conditions. The effect of crowding adults on fecundity of females was also determined. The total developmental time from egg hatching to adult eclosion ranged from 18.89 ± 0.32 to 22.5 ± 0.21 days on fresh and frozen GME, respectively. Survival per cent from egg hatching to adult emergence differed significantly when the predator fed on the two diets of GME. Also, pupal and adult weights were affected by feeding on fresh and frozen GME. There were no significant differences in longevity of females, while there were significant variations in fecundity of females and longevity of males. The calculated values of T , DT , R_o , r_m , and e^rm were high by feeding on fresh GME. Morever, rates of survivorship ( Lx ), and maximum oviposition per female per day ( Mx ) were higher when the predator was reared on fresh than on frozen GME. Crowding conditions of predator adults affected the fecundity of females due to egg cannibalism by both males and females of the predator.     

Life cycle assessment of biofuels from Jatropha curcas in West Africa: a field study

In recent years, liquid biofuels for transport have benefited from significant political support due to their potential role in curbing climate change and reducing our dependence on fossil fuels. They may also participate to rural development by providing new markets for agricultural production. However, the growth of energy crops has raised concerns due to their high consumption of conventional fuels, fertilizers and pesticides, their impacts on ecosystems and their competition for arable land with food crops. Low-input species such as Jatropha curcas , a perennial, inedible crop well adapted to semiarid regions, has received much interest as a new alternative for biofuel production, minimizing adverse effects on the environment and food supply. Here, we used life-cycle assessment to quantify the benefits of J. curcas biofuel production in West Africa in terms of greenhouse gas emissions and fossil energy use, compared with fossil diesel fuel and other biofuels. Biodiesel from J. curcas has a much higher performance than current biofuels, relative to oil-derived diesel fuels. Under West Africa conditions, J. curcas biodiesel allows a 72% saving in greenhouse gas emissions compared with conventional diesel fuel, and its energy yield (the ratio of biodiesel energy output to fossil energy input) is 4.7. J. curcas production studied is eco-compatible for the impacts under consideration and fits into the context of sustainable development.     

Aframomum melegueta: a potential botanical pesticide against Sitotroga cerealella infestation on two paddy varieties

This study was conducted to investigate the potential of Aframomum melegueta leaf and seed as biopesticide against Sitotroga cerealella infestation on two paddy varieties at ambient temperature of 28 °C ± 2 °C and relative humidity of 75?±?5%. The two paddy varieties used were FARO 44 and FARO 52. Leaf and seed powders of A. melegueta were made at 0.1, 0.2, 0.4, 0.6 and 0.8 g while the extracts were made at 1, 2, 3, 4 and 5%. Mortality of the insect on the two paddy varieties was record after 24, 48 and 72?h of application of the powders and extracts of this plant. The highest number of the insect was observed on FARO 52 treated with seed powders and extracts of A. melegueta. Only the seed extracts were able to achieve 100% moth mortality within 72 h of application at 4% concentration and were significantly (p?<?0.05) different from others. The powders and extracts of the plant significantly reduced or prevented the adult emergence of the insect and increased their developmental period as well reduced or prevented seed weight loss with seed powders and extracts having the greatest effect on the paddy variety FARO 44. The antinutritional components present in the two paddy varieties include phytate, oxalate, total phenol and tannin cyanide, and the amylase content was also determined, with FARO 44 having the highest value of 17.31, 0.18, 0.43, 10.46 and 5.49 for phytate, oxalate, tannin, cyanide and amylase content, respectively. Powders and extracts of A. melegueta could be introduced into pest management techniques since they are effective against S. cerealella.     

Progeny production by Tribolium castaneum (Coleoptera: Tenebrionidae) and Oryzaephilus surinamensis (Coleoptera: Silvanidae) on maize previously infested by Sitotroga cerealella (Lepidoptera: Gelechiidae)

A laboratory experiment was conducted to quantify the effects of infestation of maize by Sitotroga cerealella (Olivier) on progeny production by two common secondary colonizers of grain, Tribolium castaneum (Herbst) and Oryzaephilus surinamensis (L.). Adults of both secondary pest species were allowed to oviposit for 3 wk on intact kernels of 'DeKalb 689', mechanically split kernels, kernels that had been infested for 3 mo by S. cerealella, and kernels that had been infested for 6 mo. Progeny of both species reached highest numbers on 6-mo infested maize. Prior infestation for 6 mo by S. cerealella makes maize a more suitable medium for reproduction by T. castaneum and O. surinamensis, much more than can be accounted for by mere disruption of kernel integrity resulting from larval feeding. The results highlight the importance of limiting establishment by S. cerealella on maize in storage.     

冬虫夏草寄主蒲氏钩蝠蛾实验种群生命表

蒲氏钩蝠蛾Thitarodes pui是分布在西藏色季拉山的冬虫夏草寄主昆虫种类之一,海拔分布范围4100～4650m,完成一个世代需要3～4年,其中幼虫期漫长,经过7～9次蜕皮、历时990～1350d才能完成发育,环境条件变化及天敌因子等都对蒲氏钩蝠蛾的种群稳定产生重要影响。采用分段饲养幼虫的方法,构建了蒲氏钩蝠蛾试验种群生命表,并分析了种群增长趋势。结果表明,蒲氏钩蝠蛾的世代总存活率为2.6%,种群趋势指数为7.95,下代数量将是当代数量的7.95倍。因此,低存活率仍能维持蒲氏钩蝠蛾实验种群的稳定增长。     

The Abantis species (Lepidoptera: Hesperiidae) of western West Africa

Abstract. The genus Abantis Hopffer contains eight species in western West Africa. One species, Abantis pseudonigeriana sp.n., is described as new. Distributional notes and a key are given for all species. In general the species of this genus are rare and poorly represented in collections, but there are interesting examples of pairs of very similar species (nigeriana and pseudonigeriana; elegantula and maesseni).     

Life table studies of Elasmopalpus lignosellus (Lepidoptera: Pyralidae) on sugarcane

The lesser cornstalk borer, Elasmopalpus lignosellus (Zeller) (Lepidoptera: Pyralidae) is an important pest of sugarcane (a complex hybrid of Saccharum spp.) in southern Florida. Reproductive and life table parameters for E. lignosellus were examined at nine constant temperatures from 13 to 36 °C with sugarcane as the larval food source. The pre- and postoviposition periods decreased with increasing temperatures and reached their minimums at 33 and 36 °C, respectively. The oviposition period was longest at 27 °C. The mean fecundity, stage-specific survival, stage-specific fecundity, intrinsic rate of increase, and finite rate of increase were greatest at 30 °C and decreased with increasing or decreasing temperature. The net reproductive rate was greatest at 27 °C. The Logan-6 model best described the relationship between temperature and intrinsic rate of increase. The generation and population doubling times were longest at 13 and shortest at 33 and 30 °C, respectively. The most favorable temperatures for E. lignosellus population growth were between 27 and 33°C. Life table parameters for E. lignosellus reared on sugarcane were greater than for the Mexican rice borer [Eoreuma loftini (Dyar) (Lepidoptera: Crambidae)] reared on an artificial diet at 30 °C. The intrinsic rates of increase for the sugarcane borer [Diatraea saccharalis (F.) (Lepidoptera: Crambidae)] reared on sugarcane or corn were the same as for E. lignosellus reared on sugarcane at 27 °C, but the net reproductive rate was four times higher for the former than the latter borer species.     

A new species of Acraea Fabricius (Lepidoptera: Nymphalidae: Acraeinae) from Ghana, West Africa

Acraea kraka is a distinctive species, with reduced scales on both forewings and hindwings, from the equatorial forest east of the Dahomey Gap. A similar, allopatric species, A.kibi sp.n., is described from an isolated upland forest within the equatorial forest west of the Dahomey Gap.     

Efficacy of some plants powder and extract in the management of Angoumois grain moth,Sitotroga cerealella (Olivier) [Lepidoptera: Gelechiidae] infesting stored wheat grains

Powders and extracts prepared from part and products of four plants species indigenous to Nigeria were tested under laboratory condition at 28?±?2?°C and 75?±?5% relative humidity for their insecticidal potential against Angoumois grain moth, Sitotroga cerealella. Adult S. cerealella were exposed to three concentrations at rate 0.5, 1 and 2?g of Capsicum frutescens, Cymbopogon citratus, Moringa oleifera and Anacardium occidentale powders and extracts at the rate of 1, 2 and 3%/20?g of wheat grains. Parameters evaluated were adult moth mortality, adult emergence and % hatchability in treated wheat grains after infestation. Results show that significant differences (p?<?0.05) existed among the powders and the concentrations. The powder of C. frutescens had the highest mortality rate of 100% after two?days of application at all tested concentrations. There were no adult emergence of moth in samples treated with C. frutescens and A. occidentale powders. The extracts completely killed all the adult moths introduced at all tested concentrations. The survival of the moth from egg to adult when treated with the plant powders showed that there was significantly (p?<?0.05) more adult in the control (71.3) compared to others. Extracts of all the tested plants were toxic to adult moth and also prevent hatching of the eggs of S. cerealella.     

Field and storage testing Bt potatoes for resistance to potato tuberworm (Lepidoptera: Gelichiidae)

Potato tuberworm, Phthorimaea operculella (Zeller), is the most serious insect pest of potatoes worldwide. The introduction of the Bacillus thuringiensis (Bt) toxin gene through genetic engineering offers host plant resistance for the management of potato tuberworm. We report on the field and storage studies to evaluate Bt-cry5 potato lines for resistance to potato tuberworm in Egypt under natural infestations and their agronomic performance in both Egypt and Michigan. From 1997 to 2001, field experiments were conducted at the International Potato Center (CIP) Research Station, Kafr El-Zyat, Egypt, and/or Agricultural Genetic Engineering Institute (AGERI), Giza, Egypt, to evaluate resistance to tuberworm. A total of 27 Bt-transgenic potato lines from six different Bt constructs were evaluated over a 5-yr period. After harvest and evaluation of the agronomic trials, storage evaluation of potato tuberworm damage was done at the CIP Research Station. The 1997 field trial was the first field test of genetically engineered crops in Egypt. Field tests to assess potato tuberworm resistance in Egypt were able to differentiate between the Bt-transgenic lines and the nontransgenic lines/cultivars in 1999, 2000, and 2001. The Bt-cry5-Spunta lines (Spunta-G2, Spunta-G3, and Spunta-6a3) were the most resistant lines in field with 99-100% of tubers free of damage. In the 2001 storage study, these lines were also over 90% free of tuberworm damage after 3 mo. NYL235-4.13, which combines glandular trichomes with the Bt-cry5/gus fusion construct, also had a high percentage of clean tubers in the field studies. In agronomic field trials in Michigan from 1997 to 2001, the Bt-transgenic lines in most instances performed similar to the nontransgenic line in the agronomic trials; however, in Egypt (1998-1999), the yields were less than one-half of those in Michigan. Expression of the Bt-cry5 gene in the potato tuber and foliage will provide the seed producer and grower a tool in which to reduce potato tuberworm damage to the tuber crop in the field and storage.     

Quality control of the parasitoid wasp Trichogramma brassicae(Hymenoptera:Trichogrammatidae)over 45 generations of rearing on Sitotroga cerealella

Trichogramma brassicae(Bezdenko)is an important biological control agent that has been used widely against many lepidopteran pests.Commonly,colonies of Tri-chog...     

First report of the fall armyworm,Spodoptera frugiperda (Lepidoptera: Noctuidae), natural enemies from Africa

The fall armyworm (FAW), Spodoptera frugiperda, is a major pest of maize in North and South America. It was first reported from Africa in 2016 and currently established as a major invasive pest of maize. A survey was conducted to explore for natural enemies of the fall armyworm in Ethiopia, Kenya and Tanzania in 2017. Smallholder maize farms were randomly selected and surveyed in the three countries. Five different species of parasitoids were recovered from fall armyworm eggs and larvae, including four within the Hymenoptera and one Dipteran. These species are new associations with FAW and were never reported before from Africa, North and South America. In Ethiopia, Cotesia icipe was the dominant larval parasitoid with parasitism ranging from 33.8% to 45.3%, while in Kenya, the tachinid fly, Palexorista zonata, was the primary parasitoid with 12.5% parasitism. Charops ater and Coccygidium luteum were the most common parasitoids in Kenya and Tanzania with parasitism ranging from 6 to 12%, and 4 to 8.3%, respectively. Although fall armyworm has rapidly spread throughout these three countries, we were encouraged to see a reasonable level of biological control in place. This study is of paramount importance in designing a biological control program for fall armyworm, either through conservation of native natural enemies or augmentative release.     

Life table of Xylocoris afer (Hemiptera: Anthocoridae) feeding on eggs of Corcyra cephalonica (Lepidoptera: Pyralidae) and Plutella xylostella (Lepidoptera: Plutellidae)

The aim was to evaluate the biological aspects of Xylocoris afer fed on Corcyra cephalonica and Plutella xylostella eggs. The experiment was conducted with X. afer nymphs aged 12–24?h, one per Petri dish, resulting in a total of 60 nymphs (60 repetitions). On each dish, we placed P. xylostella and C. cephalonica eggs daily, together with a cotton roll moistened with distilled water and conducted daily evaluations. We evaluated the duration, viability, and consumption of nymphal stages, the longevity of males and females, the number of eggs per female, and egg fertility. In addition, the biological data were used to determine the parameters of the fertility life table. The consumption by adults (male and female) of X. afer differed between the preys, the highest consumption was C. cephalonica eggs. Females that consumed eggs of C. cephalonica produced about 90% more eggs and more offspring than those that fed on P. xylostella eggs. Based on our results, it can be inferred that the predator completed its development feeding both on natural prey and the alternative, evidencing the possible potential of X. afer to be used in the biological control of P. xylostella as well as the use of C. cephalonica in mass rearing of this predator under laboratory conditions, aiming its use in applied biological control. However, before being accepted for biological control agent against agricultural pests, various factors should be examined in ecosystem level, as the behavior of predator in different densities of prey.