Oviposition, development, and reproduction of Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) fed on different hosts of economic importance

The host selection for oviposition by Spodoptera frugiperda (J.E. Smith) among corn, millet, cotton and soybean, and its relationship with the biological characteristics were investigated. Free and non-choice tests for oviposition using plots containing five plants each, from each host in plastic greenhouse, resulted in similar oviposition preference among the host plants. In addition, selected biological characteristics of S. frugiperda were determined in the laboratory with larvae feeding on host leaves, and the combination of leaf and cotton boll. Neonate larvae exhibited low success of colonization on cotton boll compared to the leaves of all other hosts. Spodoptera frugiperda fed only on cotton bolls exhibited longer larval and pupal development, and longer adult life span; however with similar egg production. Larvae fed cotton leaves during six days and then transferred to cotton bolls, however, exhibited development and reproduction similar to those reared on corn or only on cotton leaves. Therefore, the variations on immature stages of S. frugiperda were not related with host selection for oviposition which was similar among the studied hosts. Based on our data, the millet as a winter, rotational, and cover crop is a potential host for S. frugiperda, while leaves and cotton bolls were diets of intermediate suitability as compared to corn and soybean leaves.     

Susceptibility of Anthonomus grandis (cotton boll weevil) and Spodoptera frugiperda (fall armyworm) to a cry1ia-type toxin from a Brazilian Bacillus thuringiensis strain

Different isolates of the soil bacterium Bacillus thuringiensis produce multiple crystal (Cry) proteins toxic to a variety of insects, nematodes and protozoans. These insecticidal Cry toxins are known to be active against specific insect orders, being harmless to mammals, birds, amphibians, and reptiles. Due to these characteristics, genes encoding several Cry toxins have been engineered in order to be expressed by a variety of crop plants to control insectpests. The cotton boll weevil, Anthonomus grandis, and the fall armyworm, Spodoptera frugiperda, are the major economically devastating pests of cotton crop in Brazil, causing severe losses, mainly due to their endophytic habit, which results in damages to the cotton boll and floral bud structures. A cry1Ia-type gene, designated cry1Ia12, was isolated and cloned from the Bt S811 strain. Nucleotide sequencing of the cry1Ia12 gene revealed an open reading frame of 2160 bp, encoding a protein of 719 amino acid residues in length, with a predicted molecular mass of 81 kDa. The amino acid sequence of Cry1Ia12 is 99% identical to the known Cry1Ia proteins and differs from them only in one or two amino acid residues positioned along the three domains involved in the insecticidal activity of the toxin. The recombinant Cry1Ia12 protein, corresponding to the cry1Ia12 gene expressed in Escherichia coli cells, showed moderate toxicity towards first instar larvae of both cotton boll weevil and fall armyworm. The highest concentration of the recombinant Cry1Ia12 tested to achieve the maximum toxicities against cotton boll weevil larvae and fall armyworm larvae were 230 microg/mL and 5 microg/mL, respectively. The herein demonstrated insecticidal activity of the recombinant Cry1Ia12 toxin against cotton boll weevil and fall armyworm larvae opens promising perspectives for the genetic engineering of cotton crop resistant to both these devastating pests in Brazil.     

Abscission of cotton flower buds and petioles caused by protein from boll weevil larvae

Protein extracted from boll weevil larvae causes abscission of cotton flower buds and debladed petioles. Abscission of buds is preceded by a rapid and persistent flaring of bracts; cell proliferation is induced in the abscission zone of debladed petioles. A possible mode of transmission of the agent from larva to bud tissue is discussed.     

Reducing boll weevil populations by clipping terminal buds and removing abscised fruiting bodies

Cotton pests damaging fruiting bodies (squares and young bolls) are difficult to control and their damage results in direct yield loss. Small growers, with low technological inputs, represent a large portion of cotton growers worldwide comprising more than 76 countries; they rely mainly on cultural practices to counteract pest attack in their crops. Boll weevil, Anthonomus grandis Boheman (Coleoptera: Curculionidae), oviposition involves puncturing cotton squares and young bolls, causing abscission. We examined the impact on boll weevil population of collecting abscised cotton fruiting bodies and clipping plant terminals at 50% boll maturation in the field during two cotton‐growing seasons and under field cage conditions. Greatest numbers of damaged squares occurred ca. 117 days after planting and clipped plants resulted in reduction of abscised structures and adult boll weevils compared with non‐clipped plants, irrespective of cotton variety. Damaged young bolls were found ca. 128 days after planting in 2009 and 2011, but clipping had no effect. Numbers of boll weevils found in plants of the varieties BRS 201 and BRS Rubi (both in 2009) and BRS Rubi (in 2011) were, respectively, 13‐, 17‐, and 20‐fold greater when clipping plus collecting abscised fruiting bodies were not practiced. Furthermore, the average percentage of the boll weevil parasitoid Bracon vulgaris Ashmead (Hymenoptera: Braconidae) emerging from abscised and collected structures was similar between clipped and non‐clipped plant terminals in both seasons. Clipping plant terminals did not result in yield reduction and reduced adult boll weevil production. Collecting abscised reproductive structures, clipping plant terminals, and using both practices together reduced boll weevil populations by as much as 63, 57, and 79%, respectively, in cage trials. Thus, these practices cause significant impact on boll weevil populations and are feasible of adoption, especially for smallholder cotton growers.     

苗期遮荫对棉花产量与品质形成的影响

为揭示棉麦两熟共生期遮荫对棉花产量与品质形成的影响。在棉花苗期利用模拟棉麦两熟共生期遮荫的方法进行了研究。结果表明,遮荫对棉铃形成的影响因果枝,果节部位而异,遮荫有利于棉株下（1-3果枝）,中（4-6果枝）,上（7-9果枝）部果枝内围（1-2果节）铃的形成,对外围（≥3果节）尤其顶部果枝（≥10果枝）外围铃形成不利,从而决定铃重也随果枝,果节部位相应地变化,但遮荫对单株平均铃重的影响畔 小,变遮荫棉花籽棉产量而论,下,中部果枝的内围铃籽棉产量高于常规棉,在上,顶部果枝则相反,各部位果枝外围铃的籽棉产量均低于常规棉,遮荫棉花内,外围铃分布为1：0.36(常规棉为1：0.58),产量分布为1：0.42(常规棉为1：0.72)。苗期遮荫对棉纤维,棉籽品质性状的影响也主要在顶部果枝和上部果枝外围铃,综合分析遮荫棉花产量与品质的形成,棉花苗期耐遮荫性品种间存在差异。在本研究中以中9418耐遮荫性最强,中棉所19和春矮早次之。     

江苏沿江棉区3代棉铃虫对棉花的为害及经济阈值

通过人工接虫为害,研究了3代棉铃虫对蕾铃脱落及结铃的影响,观察了不同年份棉铃虫卵和各龄幼虫的自然存活率及棉花蕾、幼铃的成铃率。结果表明,蕾铃的虫害脱落率对结铃的影响最大,直接通径系数达－0.8917,虫量和蕾铃脱落数主要通过接虫期间的虫害脱落率影响棉花结铃,其间接通径系数分别为－0.8894和-0.891,接虫期间的自然脱落率对结铃的直接和间接通径系数均很小,表明33代棉铃虫为害时棉花4的补偿能力已基本丧失,各龄幼虫的为害量观察表明,1－6龄幼虫的单虫为害当量分别为0.02、0.14、0.31、0.47、0.84和1.54个大铃,根据防治的直接和间接收益,得出3代棉铃虫的防治指标为百株累计卵量26粒。     

Factors affecting regulation of maternal investment in an indeterminate flowering plant (Cercidium microphyllum; Fabaceae)

On palo verde trees, nearly 80% of potential offspring were lost during flower bud development. Flower buds at the base of racemes developed earliest and were more likely to survive depredations of gelechiid larvae or abortion from putative limited resources. Herbivory accounted for greater cumulative losses than putative resources; however, an herbivore exclusion experiment suggested that buds damaged by herbivores would have aborted anyway without damage. In a natural experiment, plants that received water runoff had significantly higher densities of racemes, with only slight increases in numbers of buds, flowers, or pods per raceme. Similarly, thinning racemes experimentally to assess limited resources among potentially competing racemes increased the number of viable flower buds per raceme only slightly, with negligible herbivore damage. The production of more racemes rather than more reproductive structures per raceme may be a mechanism to allocate limited resources more efficiently. Alternatively, in studies with animals, similar patterns in the production of broods are thought to be mechanisms to avoid nest predation. Thus, while putative limited resources and resource allocation patterns reduced the proximate effects of larvae, herbivory must be considered as a possible ultimate factor in the patterns observed here because limited resources may be allocated in ways to reduce herbivory.     

Suppression of cotton leafworm Spodoptera litura, flower beetle Mylabris pustulata and red cotton bug Dysdercus cingulatus by Rhynocoris marginatus (Fabr.) (Het., Reduviidae) in cotton field cages

Abstract: Mass-reared reduviid, Rhynocoris marginatus was released in large-sized cotton field cages against three cotton pests, Spodoptera litura, Mylabris pustulata and Dysdercus cingulatus . Pest species were introduced into separate cages in the absence of other pests, parasitoids and predators. Control experimental cages without R. marginatus were maintained for each prey set up during the evaluation period. R. marginatus greatly reduced the infestation of S. litura (57.5%), M. pustulata (52.3%) and D. cingulatus (45.8%). The leaves, flower and boll damages (32%, 35% and 28% by S. litura, M. pustulata and D. cingulatus , respectively) and seed-cotton yield loss (1.4, 1.6 and 1.25 times in S. litura, M. pustulata and D. cingulatus infested cages, respectively) were reduced by R. marginatus compared with such fields without R. marginatus . The field observations suggest this predator's pest suppression and damage reduction efficacy.     

棉铃虫的取食营养特点与棉花抗虫素分布的关系

通过研究棉花8个部位对棉铃虫Helicoverpa armzgera的营养效果和其所含次生物质类萜烯和单宁的浓度及在组织中的分布,揭示了棉铃虫取食营养特点与棉花次生化学的关系。棉铃虫取食顶尖、转移蛀食蕾铃的习性,与有关器官或组织对幼虫的营养效果密切相关,而营养效果主要取决于类萜烯和单宁的含量。棉花顶尖嫩叶中单宁浓度随着棉花的生长发育呈升高的趋势;类萜烯浓度在第四真叶期、第六真叶期和现蕾初期之间出现一个明显的底谷,而此期幼虫主要为害顶尖。蕾铃外层的苞叶、花萼、花瓣和铃皮,因次生物质含量高,不利于幼虫生长,相反内部的花粉、子房和铃心,次生物质含量低,营养效果好,顶尖嫩叶则介于其间。类萜烯存在于组织的色素腺内,分布集中;单宁则散布于组织中,偏多分布于组织外层。结果证实,昆虫在寄主植物上的取食方式是昆虫对寄主体内变动的次生化学的一种适应,它使昆虫付出尽少代价获得最适营养效果。     

Bioenergy crops Miscanthus x giganteus and Panicum virgatum reduce growth and survivorship of Spodoptera frugiperda (Lepidoptera: Noctuidae)

Large-scale cultivation of plants used as biofuels is likely to alter the ecological interactions of current agricultural crops and their insect pests in a myriad of ways. Recent evidence suggests many contemporary maize pests will be able to use potential biofuel crops such as switchgrass, Panicum virgatum L., and miscanthus as hosts. To determine how suitable these biofuels are to the maize, Zea mays L., pest and generalist graminivore, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), we examined host plant preference and larval performance on foliage grown for commercial biofuel production. Larvae fed leaf tissue from both field- and greenhouse-grown switchgrass and miscanthus were monitored for survival, development, and food use relative to field-grown maize. Survivorship on biofuel crops was high on greenhouse-grown leaf tissue but severely reduced for field-grown switchgrass, and no larvae survived on field-grown miscanthus. Larvae fed field-grown tissue had larger head capsules yet achieved lower pupal weights because the increased toughness of the leaf tissue prevented the assimilation of nitrogen. Given that larvae overwhelmingly preferred maize to other biofuel crop species and that survival and performance were dramatically reduced on biofuel crop species, it is likely that biofuel crops, as grown for field cultivation, will suffer reduced damage from maize pests such as S. frugiperda because of reduced suitability.     

Comparative production of Helicoverpa zea (Lepidoptera: Noctuidae) from transgenic cotton expressing either one or two Bacillus thuringiensis proteins with and without insecticide oversprays

Transgenic cotton, Gossypium hirsutum (L.), expressing either one or two Bacillus thuringiensis ssp. kurstaki Berliner (Bt) proteins was compared with the conventional sister line in field experiments with regard to production of bollworm, Helicoverpa zea (Boddie), and bolls damaged by bollworm. The relative numbers of bollworms that developed on Bollgard (Monsanto Co., St. Louis, MO), Bollgard II (Monsanto Co.), and conventional cotton were estimated under nontreated conditions in 2000 and both insecticide-treated and nontreated conditions in 2001-2002 in North Carolina tests. Averaged across seven field studies under nontreated conditions, Bollgard cotton generated statistically similar numbers of large (L4-L5) bollworm larvae compared with the conventional variety; however, Bollgard cotton produced significantly fewer damaged bolls and bollworm adults than the conventional variety. Production of large larvae, damaged bolls, and adults was decreased dramatically by Bollgard II cotton as compared with Bollgard and conventional varieties. When comparing insecticide-treated and nontreated cotton genotypes, both Bt cotton sustained less boll damage than the conventional variety averaged across insecticide regimes; furthermore, Bollgard II cotton had fewer damaged bolls than the Bollgard variety. When averaged across cotton genotypes, pyrethroid oversprays reduced the numbers of damaged bolls compared with the nontreated cotton. Insecticide-treated Bollgard cotton, along with insecticide-treated and nontreated Bollgard II cotton reduced production of bollworm larvae, pupae, and adults. However, the addition of pyrethroid oversprays to Bollgard II cotton seemed to be the best resistance management strategy available for bollworm because no bollworms were capable of completing development under these conditions.     

Modeling Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) damages on cotton

We studied and modeled damage caused by Helicoverpa armigera larvae on cotton with the aim of developing a coupled crop pest model. Two damage components were studied: the voracity (quantity of fresh matter and number of organs consumed) and feeding preferences (type of organ infested). The laboratory no-choice study of voracity on excised squares and bolls revealed that an H. armigera larva consumes 2,856 mg of fresh matter throughout its larval life, with the sixth instar consuming 86% of this quantity. This consumption rate corresponded to 23.6 squares, or 7.8 bolls. We developed equations to predict the quantity of fresh matter uptake from an individual plant organ, according to the organ mass and the larval instar. The field study of feeding preference confirmed previous findings that larvae prefer squares to bolls, with this preference decreasing as the larval age increases. However, no significant relationship was noted between the age of larvae and the size of infested organs within each organ class (square or boll). We developed a logistic model to predict the probability of a larva infesting a boll rather than a square. According to this model, the relative organ availability in the field and the larval instar were found to be significant factors.     

华北棉区棉铃虫种群动态与其为害特征分析

本文述及棉铃虫为害特性及其与为害后棉株的补偿作用关系。根据棉株生命表资料,蕾期棉株蕾花的脱落主要系由棉铃虫为害所致。而铃期蕾铃的脱落,则主要系由棉株的生理条件。在蕾期,前三周内蕾花被害脱落后,棉株的补偿作用是很高的,从第四周起补偿作用逐渐下降,而到铃期阶段时补偿作用降至很低水平。因此蕾期棉株遭受一定数量以内的棉铃虫为害,而使蕾花脱落后,反而可促使棉花增产。根据棉铃虫生命表资料,从卵期至三龄末幼虫期的累计死亡率占总死亡率的90%以上,结合幼虫死亡率与不同龄期为害水平分析,棉铃虫对棉株的主要为害阶段系在2—3龄期,其对果实的为害量占总为害的65%。而棉株被害蕾铃的田间空间分布型系遵从负二项分布,期公共K值为3.4626。     

Transmission of Alternaria macrospora in Cotton Seeds

Alternaria macrospora was isolated from seeds only after the natural opening of the bolls and exposure of seeds to an environment in which the fungus was present. The fungus lacks the ability to penetrate the boll wall and reach the seed site. Attempts to isolate the pathogen from seeds of immature bolls at different developmental stages failed. Internal infection by slow injection resulted in seed infection and partial shedding of the injected plant parts which was high in buds and decreased with the ripening to mature bolls. Severity of seed infection was not dependent on either inoculum level, boll physiological age or even if the boll itself was not diseased. Infection of flowers under field conditions caused flower shedding. Naturally infected seeds or inoculated seeds with inoculum levels of 100 spores/ml and above resulted in diseased cotyledons, the incidence of which was, for inoculated seeds, positively correlated with inoculum level. A small difference was observed between cultivars in susceptibility to artificial inoculation at the cotyledon stage. A. macrospora survived on commercial cotton seeds and on post-season plants left growing at the field edges. Survival in plant debris under field conditions was minimal and may only have a minor effect on field reinfestation.     

Switching among natal and auxiliary hosts increases vulnerability of Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) to insecticides

The role of insecticidal application and host plant resistance in managing Spodoptera exigua has been well documented, but the effect of different host plants, on which the pest cycles its population in the field, has seldom been investigated. Therefore, we have studied the vulnerability of S. exigua against commonly used insecticides (cypermethrin, chlorpyrifos, lufenuron, and emamectin benzoate) with different mode of actions when it switches its generations from natal to auxiliary hosts and vice versa. Different field populations being established on different host plants including castor, cauliflower, cotton, okra, and spinach were collected and reared in the laboratory before insecticidal bioassays. The role of larval diet and host plant switching on their response to tolerate applied insecticides was studied using leaf‐dip bioassay methods. Host switching demonstrated a significant role in altering the vulnerability of S. exigua populations to tested insecticides. Spodoptera exigua sourced from castor, when switched host to okra and spinach, exhibited 50% higher mortality when treated with emamectin benzoate. This trend in mortality was consistent upon complete host switch cycle (natal—auxiliary—natal host). However, the highest increase (92%) in vulnerability was recorded when the larvae were shifted to spinach from cotton. In general, chlorpyrifos and lufenuron had highest efficacies in terms of larval mortality. The findings of present studies provide insights to a better understanding the behavior of polyphagous pests and the role of different host plants in altering the susceptibility of these pests against applied insecticides. Ultimately the results warrant that due consideration should be given to cropping patterns and time of host switching by pest population during planning and executing chemical control.     

Feeding of fall armyworm,Spodoptera frugiperda,on Bt transgenic cotton and its isoline

Studies on insect food intake and utilization are important for determining the degree of insect/plant association and host species’ resistance, and also for helping design pest management programs by providing estimates of potential economic losses, techniques for mass breeding of insects, and identifying physiological differences between species. We studied the feeding and development of fall armyworm, Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae), on transgenic (Bt) and non‐transgenic (non‐Bt) cotton. The larvae of S. frugiperda fed on Bt cotton had a longer development period (23.0 days) than those fed on non‐Bt cotton (20.2 days). Survivorship of S. frugiperda larvae fed on Bt cotton (74.1%) was lower than that of larvae fed on non‐Bt cotton (96.7%). Pupal weight of larvae fed on Bt cotton (0.042 g) was lower than that of larvae fed on non‐Bt cotton (0.061 g). The cotton cultivar significantly affected food intake, feces production, metabolization, and food assimilation by S. frugiperda larvae. However, it did not affect their weight gain. Intake of Bt‐cotton leaf (0.53 g dry weight) per S. frugiperda larva was lower than the intake of non‐Bt‐cotton leaf (0.61 g dry weight). Larvae fed on Bt‐cotton leaves produced less feces (0.25 g dry weight) than those fed on non‐Bt‐cotton leaves (0.37 g dry weight). Weight gain per S. frugiperda larva fed on Bt‐cotton leaves (0.058 g dry weight) was similar to the weight gain for larvae fed on non‐Bt‐cotton leaves (0.056 g dry weight). The cotton cultivar significantly affected the relative growth, consumption, and metabolic rates, as well as other nutritional indices: the figures were lower for larvae fed on Bt‐cotton leaves than for larvae fed on non‐transgenic cotton leaves.     

Injury to preflowering and flowering cotton by brown stink bug and southern green stink bug

The impact of brown stink bug, Euschistus servus (Say), and southern green stink bug, Nezara viridula (L.), injury was evaluated on preflowering and flowering cotton, Gossypium hirsutum L., plants in no-choice tests. Vegetative stage cotton seedlings and reproductive structures, including flower buds (square) and bolls, were infested with adults and/or nymphs of both species. There were no significant differences in height, height to node ratio, square retention, and flower initiation for cotton seedlings or plants with a match-head square between southern green stink bug adult- or brown stink bug adult-infested and noninfested treatments. Abscission for individual large squares (precandle) and multiple squares (medium and small square on the same sympodial branch) was not significantly different among infested and noninfested treatments for the following species and developmental stages: brown stink bug adults, southern green stink bug adults, and third and fourth to fifth instar southern green stink bug nymphs. In boll infestation studies, the relationship between boll maturity, expressed as heat units beyond anthesis, and boll growth, abscission, hard locked carpels, seedcotton yield, and seed germination was measured. Brown stink bug induced abscission in bolls that had accumulated > 0-350 heat units beyond anthesis. Boll growth and seedcotton yield was significantly lower for bolls infested with brown stink bug through 266.5 and 550 heat units beyond anthesis, respectively. The proportion of hard locked carpels per boll was significantly greater for the infested treatment in a cohort of bolls that accumulated from 51 to 400 heat units beyond anthesis. Seed germination in bolls infested with brown stink bug was significantly lower in bolls aged 101-600 heat units beyond anthesis.     

Population dynamics of caterpillars on three cover crops before sowing cotton in Mato Grosso (Brazil)

Direct seeding mulch-based cropping systems under a preliminary cover crop such as millet are common in some areas of Brazil. Lepidopteran pests that damage cotton, soybean and maize crops can proliferate on cover crops, so preventive chemical treatments are necessary. Very little data is available on these pests on cover crops. This paper presents the dynamics of Spodoptera frugiperda, S. eridania, Mocis latipes and Diatraea saccharalis caterpillars monitored at Primavera do Leste, Mato Grosso state (Brazil) during the of 2005/2006 and 2006/2007 cropping seasons on four cover crops, i.e. finger millet (Eleusine coracana), pearl millet (Pennisetum glaucum), sorghum (Sorghum bicolor) and ruzigrass (Brachiaria ruziziensis). The pests were visually counted on plants within a 1 m2 transect (wooden frame). Caterpillars were reared to facilitate identification of collected species and parasitoids. Many S. frugiperda caterpillars were observed on millet in 2005, with a maximum of 37 caterpillars/m2. On sorghum, we found 30 caterpillars/m2, or 0.83 caterpillars/plant. The Diatraea borer attacked sorghum later than the other pests. M. latipes was also observed on millet. The millet cover crop had to be dried for at least 1 month before direct drilling the main cotton crop in order to impede S. frugiperda infestations on cotton plantlets, thus avoiding the need for substantial resowing. The comparative methodological aspects are discussed.     

Biological performance of quercetin on the cotton leaf-worm larvae, Spodoptera littoralis Boisd. (Lep., Noctuidae) and prevailing natural enemies in the Egyptian cotton fields

The Egyptian cotton (Gossypium barbadense L.) accounts for 65 % of the world production of long stable cultivars. Taking into consideration the competition of other cotton producing countries, it should be of great importance to control pests, which attack the cotton plants to improve the yield and its quality. The main objective of this study is to develop new approaches for the management of the cotton leafworm Spodoptera littoralis Boisd. within an IPM program, that include synthetic insecticides rationalization, and maximiziation the role of the biological control agents. Sunflower plants Helianthus annuus (Asterales: Asteraceae) raised in rows surrounding plots of cotton were used as trap plants to attract some biological agents, which subsequently lead to check the build-up of the cotton leafworm population. This scientific phenomenon was attributed to the main chemical constituent of sunflower plants, which has been proved to be the polyhydroxy flavone "quercetin". Field data of the two successive seasons 2004 and 2005 revealed that: (a) the total number of insect predators, Coccinella undecimpunctata, Paederus alfierli, Chrysopa vulgaris, Orius laevigatus, Scymnus synacus, and true spiders in the cotton plots surrounded by either one or two rows of sunflower plants significantly exceeded the corresponding numbers in the cotton plots without sunflower plants., (b) the least number of cotton leafworm Spodoptera littorolis larvae infestation was recorded simultaneously in the cotton plots surrounded by sunflower plants. Moreover, laboratory studies assured the antifeeding properties of quercetin against the 4th instar larvae of Spodoptera littoralis. Quercetin at a concentration rate of 4000 ppm, showed abnormal behaviour represented in feeding stop, growth inhibition and development retardation. Deformation of pupae, moths, and reduction up to 50% in egg laying was also noticed after quercetin application to the larvae.