The study of pesticide-fertilizer combination prepared with biochar and chlorantraniliprole and its effectiveness in controlling fall armyworms

In this research,a pesticide-fertilizer combination(PFC)was fabricated using chlorantraniliprole and biochar.The PFC had a spherical shape,smooth surface,uniform particles,relatively dense structure and good compression resistance.The adsorption propertie of biochar to chlorantraniliprole was investigated.During the preparation of pelleted granules,the types and concentrations of corefillers and adhesives were screened and optimized.Besides,the safety to maize and effectiveness against fall armyworms of PFC had been investigated.Meanwhile,The PFC could promoted growth of maize significantly and control fall armyworm effectively.This work provides a promising approach to slow the release of chlorantraniliprole,which has a potential application to enhance the pesticides efficiency.

Occurrence Law of Armyworm in China and Its Identification and Prevention

Armyworm occurs throughout the world, which mainly causes damage on grasses. The morphology characteristic of armyworm is introduced, which is also compared with the morphology characteristic of the other insects such as corn borer, Leucania Ioreyi （Duponchel） and Leucania venalba. The occurrence law, living habit and prevention measures of armyworm in China are summarized, which will provide the foundation for worldwide further research on armyworm.

Population occurrence of the fall armyworm,Spodoptera frugiperda(Lepidoptera:Noctuidae),in the winter season of China

Fall armyworm(FAW),Spodoptera frugiperda(J.E.Smith),has become an important pest in Chinese agricultural systems since its invasion on 11 December 2018.After its establishment,FAW months in the year-round breeding region have become the main source population migrating to other areas in China.Field investigations were conducted in tropical and subtropical regions to improve understanding of its year-round breeding area in China.The results showed that FAW larval density was significantly correlated with the seasonal temperature of the location surveyed.The FAW larvae maintained a high density in the tropical area and were frequently found in sites of the south subtropical region,but were absent from the north subtropical region and the northern part of the central subtropical region.These results indicated that FAW can reproduce annually in the tropical and south subtropical regions of China,including Hainan,Taiwan and the southern area of Fujian,Guangdong,Guangxi,Guizhou,and Yunnan.Hence,great effort should be made to monitor and control FAW in the year-round breeding region to suppress the population density of this area and to reduce migration of moths into northern parts of China.This study clarifies the occurrence area of the pest in winter in China and provides much valuable information for its population forecasting and management.

Biology,invasion and management of the agricultural invader:Fall armyworm,Spodoptera frugiperda(Lepidoptera:Noctuidae)

The fall armyworm(FAW),Spodoptera frugiperda(J.E.Smith),is native to the Americas.It has rapidly invaded 47 African countries and 18 Asian countries since the first detection of invasion into Nigeria and Ghana in 2016.It is regarded as a super pest based on its host range(at least 353 host plants),its inherent ability to survive in a wide range of habitats,its strong migration ability,high fecundity,rapid development of resistance to insecticides/viruses and its gluttonous characteristics.The inherently superior biological characteristics of FAW contribute to its invasiveness.Integrated pest management(IPM)of FAW has relied on multiple applications of monitoring and scouting,agricultural control,chemical pesticides,viral insecticides,sex attractants,bio-control agents(parasitoids,predators and entomopathogens)and botanicals.Knowledge gaps remain to be filled to:(1)understand the invasive mechanisms of S.frugiperda;(2)understand how to prevent its further spread and(3)provide better management strategies.This review summarizes the biological characters of FAW,their association with its invasiveness and IPM strategies,which may provide further insights for future management.

Research on the invasive pest of fall armyworm(Spodoptera frugiperda)in China

The fall armyworm(Spodoptera frugiperda)is a major agricultural pest native to the Americas.It is widely distributed throughout the Western Hemisphere.It damages crops such as maize,wheat,rice,sorghum,cotton,herbage and various weeds,and reportedly feeds on more than 300 species(Montezano et al.2018).Fall army wo rm is a typical lepidoptera pest and goes through four life stages:egg,larva,pupa and adult Adults can lay eggs between 1000 and 2000 and complete a life cycle within about 30 days,reproducing at a fast speed.There are two biotypes of fall armyworm:Corn-biotype(C-strain)and Rice-biotype(R-strain).

Expression profiles of Cry1Ab protein and its insecticidal efficacy against the invasive fall armyworm for Chinese domestic GM maize DBN9936

The fall armyworm(FAW)Spodoptera frugiperda,which originated in the Americas,is advancing across China and threatening the nation’s maize crops.Currently,one widely used tool for its control is genetically modified(GM)Bacillus thuringiensis(Bt)maize.Sufficient content of Bt protein in appropriate plant parts is crucial for enhancing resistance against insect pests.In this study,we conducted a systematic investigation of Cry1 Ab levels in Chinese domestic GM maize DBN9936,which has recently obtained a biosafety certificate,and evaluated its efficacy against FAW.Quantification of expression levels of Cry1 Ab,via ELISA,indicated a spatio-temporal dynamic,with significant variation of mean Cry1 Ab,ranging from 0.76 to 8.48μg g-1 FW with the Cry1 Ab protein level ranked as:V6-V8 leaf>R1 leaf>R4 leaf>R1 silk>VT tassel>R4 kernel.Among the nine locations,the Cry1 Ab levels in DBN9936 of the Xinxiang,Langfang,and Harbin fields were significantly lower than those from Wuhan and Shenyang,and were slightly,but not significantly lower than those from the other four fields.Furthermore,the artificial diet-Cry1 Ab mixture and plant tissue feeding bioassays revealed that DBN9936 has high efficacy against FAW.The insecticidal efficacy of different tissues against FAW larvae reached 34-100%with a descending order of lethality as follows:VT leaf>R4 leaf>R1 husk>R1 silk>VT tassel>R4 kernel.Taken together,our results showed that Bt-Cry1 Ab maize DBN9936 has potential as a promising strategy to manage FAW.

Effects of alternating temperatures on development and reproduction of the armyworm,Mythimna separata (Walker)

Effects of cycling and constant temperature on development and reproduction of the armyworm, Mythimna separata (Walker) were investigated by rearing the insects on the artificial diet under temperatures covering low(16-24℃ vs. 20 ℃ ), medial(20-28℃ vs. 24℃ ) and high(24-32 ℃ vs. 28 ℃) regions. In the low region, all the immature stages of the insect developed significantly faster under alternating temperatures than at corresponding constant temperatures. For the medial region, their development was little affected by variable temperatures. For the high region, developmental durations tended to be longer under cycling temperatures except egg stage.Mean fecundities of the adult moths markedly increased under cycling temperatures as compared with those at respective constant temperature in all regions.Possible reasons for effect of alternating temperatures on insect development are discussed in some details.

Performance and Enzyme Activity of Beet Armyworm Spodoptera exigua (Hübner) (Lepidoptera:Noctuidae) Under Various Nutritional Conditions

We explored the influence of the artificial diets with different protein and glucose contents on larval development,fecundity and enzyme activities of the beet armyworm Spodoptera exigua （Hübner）.Our results suggested that development,fecundity and population growth index of beet armyworm increased with increased nutritional content in the artificial diets;however,when the yeast to cellulose content ratio reached 46.8：53.2,the fecundity and population growth had reached a maximum and additional protein did not yield additional growth.Additionally,3rd instar beet armyworm larvae fed on different artificial diets had increased enzymatic activities of acetylcholinesterase （AChE） with the increased nutritional content,but carboxylesterase （CarE） activities did not significantly change under variation in the nutritional content.

Effect of three insect-resistant maizes expressing Cry1le,Cry1Ab/Cry2Aj and Cry1Ab on the growth and development of armyworm Mythimna separata(Walker)

Three transgenic maize events(IE09S034,Shuangkang 12--5 and C0030.3.5)produced Cry1le,Cry1Ab/Cry2Aj and G10-EPSPS,Cry1Ab and EPSPS,respectively,all of which target the Asian corn borer.The oriental armyworm Mythimna separata(Walker)is the secondary target.In this study,the effects of the three Bt maizes on the development and survival of armyworm were studied.The results showed that IE09S034 had insecticidal activity against 1st instar larvae,and the survival rate of armyworm fed with Bt maize for 10 days was 462%,significantly lower than that of the control.The larvae at 3rd--6th instar were more tolerant of the Bt toxin than the early instar larvae.However,Shuangkang 12-5 had good insecticidal activity against 1st-5th instar larvae.The mortality was nearly 100%when the larvae were fed with Shuangkang 12-5 before 3rd instar,and the toxin had quick acting eficacy.This event significantly ihibited the development of armyworm;that is,the larval duration of the 3rd and 4th instar larvae fed with Shuangkang 12-5 was prolonged by 4.5 and 3.0 days,respectively.The pupal weight and egg number were also significantly lower than those of the control.For C0030.3.5,it could control 1st--5th instar larvae effectively.The mortality rates were all over 50%if 1st-3rd larvae were fed with this event.The pupal weight of 4th-6th instar larvae fed with Bt maize were only 53.9,56.8 and 54.6%,respectively,compared to that of the control.The number of eggs laid was significantly less than the control.The results indicate that all three transgenic maize events exhibit the potential to provide effective control of early instar larvae of armyworm.which can be commercialized in future to control lepidoptera pests such as Asian corn borer and armyworm.

Effects of Tebufenozide on the Biological Characteristics of Beet Armyworm (Spodoptera exigua Hübner) and Its Resistance Selection

In this article, the selection of tebufenozide to beet armyworm （Spodoptera exigua Htibner） was studied by the treatments to alternative generations＇ 3rd-instar larvae with LC50 dose and to continuous generations＇ larvae with LC10 dose; the effects of tebufenozide on the biological characteristics of current and subsequent generations were examined by the treatments to 3rd-instar larvae and egg pods in different concentrations. After treatments with LC50 dose till F11, the toxicity of tebufenozide to beet armyworm had no significant change, whereas the pupation rate, pupal weight, and fecundity were reduced markedly. After treatments with LC10 dose till Fl9, the beet armyworm only developed 3.52-fold resistance, and the main biological characteristics were nearly accordant in each generation. The livability was reduced 72 h later after treatments to 3rd-instar larvae, respectively in 2.5-40 μg mL^-1, and larval duration, pupation rate, and pupal weight changed considerably with the increase in concentrations. The fecundity, larval livability, larval weight and pupal weight of subsequent generations were reduced as the dose increased over 10 μg mL^-1. The hatching rate of egg pods did not differ with that of the controls obviously after treatment in 10-300 μg mL^-1. But the larval livability, larval weight and pupal weight were reduced when eggs were exposed to 50 μg mL^-1 dose or more. The results indicated that tebufenozide had low resistance risk to the current and subsequent generations of beet armyworm even if tebufenozide had significant effects on the biological characteristics of this insect.

Morphology Characteristic and Damage Identification of Beet Armyworm

Beet armyworm is widely distributed throughout the world,it can cause damage on many kinds of crops. Differences of morphological characteristics among beet armyworm,cabbage butterfly,cotton bollworm,cabbage armyworm and Prodenia litura（Fabricius）are compared,occurrence regulation,living habits,damage characteristics and control methods of beet armyworm are introduced.

Possible source and migration pathway for early-summer immigrants of the oriental armyworm, Mythimna separata, arriving in northern Japan

The first generation of the oriental armyworm, Mythimna separata(Walker), arrives every year in northern Japan in mainly late May to early June. Analyses of weather maps suggested that this moth’s immigration source could be eastern China, but the accuracy of those analyses was very limited due to the lack of a current standard trajectory analysis. The management of migratory insect pests such as M. separata benefits from the identification of the migration source(s)and pathway(s) of the pests. The present study provides a trajectory analysis for M. separata. Backward trajectories from trap sites in northern Japan were calculated with the HYSPLIT System developed by the U.S. National Oceanic and Atmospheric Administration, taking the flight speed of M. separata and the limitation of low ambient temperature at flight height into account. The ending times of the moth’s short and long trajectories were set at dusk on the day before and two days before the possible arrival date, respectively. The results suggested two types of possible migration pathway: a multi-step pathway from Northeast China, the Korean Peninsula, and eastern Russia, which are destination areas of the first-generation’s migration, and a direct pathway from seasonal main emigration areas in eastern China such as Jiangsu and Shandong provinces. These findings contribute to our understanding of the migration ecology of M. separata and can be used for the development of methods to predict the migration of this insect.

Regularity of population occurrence and migration in the oriental armyworm, Mythimna separata(Walker)

The oriental armyworm,Mythimna separata（Walker）（Lepidoptera：Noctuidae）,is a major migrant pest of grain in China and other Asian countries,causing huge crop production and economic losses nationwide annually.Much of the uniquely difficult aspects of managing M.separata arises from its long-distance migratory behavior.For example,direction and timing of winds from its overwintering regions in the south largely determine where and when large influxes of migrants arrive in the north to oviposit,making prediction of infestations difficult.

Perception and Level of Knowledge of the Fall Armyworm (Spodoptera frugiperda J.E. Smith) by Maize Farmers in the Southern Agricultural Zone of Niger

Maize is one of the cereals most consumed by households in Niger. Its production remains marginal despite the efforts made in hydro-agricultural development both around the Niger River and in the interior of the country. The detection of the fall armyworm (Spodoptera frugiperda J.E. Smith) in 2016 in Niger, followed by its rapid spread where in less than a year it has spread over almost the entire national territory is not without consequence on the yields of the but already very low in the main production areas. As a result, maize production is increasingly being abandoned in the southern agricultural zone of Niger. In fact, this caterpillar has become a major pest of maize because of the significant damage observed on this crop during its growth and development cycle. This situation calls for research to be conducted to help maize producers better manage this pest. The objective of this study is to assess the level of knowledge and management of FAW by maize farmers in the southern agricultural zone of Niger. A survey was conducted in July and August 2020 on a sample of 408 farmers in this zone using an individual questionnaire designed and integrated into the ODK data collection software. The results obtained showed that 93% of the producers recognize FAW through its morphology and the aspects of its damage;53.25% estimate that the attack rate is very high and 60.75% of the producers use pesticides in the management of this pest against only 1.5% who use biopesticides. These results clearly indicate the severity of FAW attacks on corn and the massive use of pesticides by producers.

Heterosis effect for larval performance of fall armyworm interstrain hybrids

Spodoptera frugiperda,also known as fall armyworm(FAW),is an invasive crop pest that can feed on a variety of host plants,posing a serious threat to food security.There are two sympatric strains of FAW that are morphologically identical but described with different food preferences:the“rice strain”(SfR)and the“corn strain”(SfC).A few genetic loci exist to identify these two strains.Mitochondrial and Z-chromosome-linked haplotypes are the most used,but the biggest part of the genome displays little polymorphism between strains that could explain their adaptation to different plants.We have previously observed consistent transcription differences between the strains in both laboratory and natural populations.Therefore,we wonder if there are effects from host-strain-associated loci,maternally or paternally inherited,on FAW performance that could explain the divergence between the two FAW strains.To test this hypothesis,we first produced two F1 hybrid generations(SfR♀×SfC♂,SfC♀×SfR♂).These reciprocal hybrids should be heterozygous for all chromosomes except for the maternally inherited mitochondrial and sexual W chromosomes.To evaluate whether plant preference is determined by these genetic loci,we cultivated the two hybrids and the two parental strains in triplicate on an artificial diet and recorded several phenotypic traits such as weight over time,survival rate,emerging rate,developmental time,and sex ratio.Then,the same performance experiment was carried out on corn plants.Surprisingly,on the artificial diet,the two hybrid genotypes were both more performant than the two parental strains in terms of survival rate,pupal emerging rate,and developmental time,whereas they were intermediate to the inbred parental strains in pupal weight.On the corn plant diet,both hybrid genotypes outperformed the two parental strains in larval weight.Although these asymmetrical results revealed that mitochondrial or sex-linked haplotypes alone cannot explain the performance differences,they suggested a heterosis effect in FAW.A reduction of the female number for the CR genotype and the decreased F1 offspring reproduction in both hybrids suggested the possibility of Haldane's rule,which might be explained by the dominance model.

Competitive interactions between invasive fall armyworm and Asian corn borer at intraspecific and interspecific level on the same feeding guild

Interspecific competition is an important factor in the population dynamics and geographical distribution of insect populations.Fall armyworm(FAW),Spodoptera frugiperda,an invasive species,and the Asian corn borer(ACB),Ostrinia furnacalis,a native pest species are major pests on maize in China,posing a threat to maize yield and grain quality.A series of laboratory,greenhouse,and field experiments were conducted to elucidate the competitive interactions between FAW and ACB.In the laboratory experiments,FAW exhibited aggressive behaviors more frequently when compared with ACB,while the latter species exhibited defense behaviors more frequently.Higher intraspecific competition was recorded in the FAW conspecific rather than in ACB,particularly in the 6th larval stage.FAW had a higher interspecific competitive advantage through intraguild predation over ACB,resulting in partial or complete displacement ACB when initially the ratio of the 2 species was 1:1.The interspecific competition also had significantly influenced on the population parameters,defensive enzymes,and nutrient of these 2 species.Competitive interaction proved that the response of superoxide,catalase,and soluble protein in FAW were significantly increased,whereas the total sugar content in both species was substantially decreased.Survival rate,and the plant damage that co-infested by both species varied significantly among the sequential combinations under greenhouse and field conditions.FAW consistently exhibited stronger intraspecific aggression than ACB under laboratory and field conditions when co-existing on the same feeding guild.These findings contribute to efforts toward the improvement of integrated pest management programs for FAW,in decision making for invasive and native pests’management strategies to reduce the high risks of FAW and ACB outbreaks.

Resistance of the fall armyworm,Spodoptera frugiperda,to transgenic Bacillus thuringiensis Cry1 F corn in the Americas:lessons and implications for Bt corn IRM in China

The fall armyworm,Spodoptera frugiperda(J.E.Smith),is a major target pest of Bt crops(e.g.,corn,cotton,and soybean)in North and South America.This pest has recently invaded Africa and Asia including China and the invasion has placed a great threat to the food security in many countries of these two continents.Due to the extensive use of Bt crops,practical resistance of S.frugiperda to Cry IF corn(TC 1507)with field control problems has widely occurred in Puerto Rico,Brazil,Argentina,and the mainland United States.Analyzing data generated from decade-long studies showed that several factors might have contributed to the wide development of the resistance.These factors include(1)limited modes of action of Bt proteins used in Bt crops;(2)cross-resistance among Cryl proteins;(3)use of nonhigh dose Bt crop traits;(4)that the resistance is complete on Bt corn plants;(5)abundant in initial Cry IF resistance alleles;and(6)lack of fitness costs/recessive fitness costs of the resistance.The long-term use of Bt crop technology in the Americas suggests that Bt corn can be an effective tool for controlling S.frugiperda in China.IRM programs for Bt corn in China should be as simple as possible to be easily adopted by small-scale growers.The following aspects may be considered in its Bt corn IRM programs:(1)use of only"high dose^traits for both S.frugiperda and stalk borers;(2)developing and implementing a combined resistance monitoring program;(3)use“gene pyramiding”as a primary IRM strategy;and(4)if possible,Bt corn may not be planted in the areas where S.frugiperda overwinters.Lessons and experience gained from the global long-term use of Bt crops should have values in improving IRM programs in the Americas,as well as for a sustainable use of Bt corn technology in China.

Trajectory modeling revealed a southwest-northeast migration corridor for fall armyworm Spodoptera frugiperda(Lepidoptera:Noctuidae)emerging from the North China Plain

The fall armyworm Spodoptera frugiperda,an invasive insect pest native to the Americas,has established populations throughout eastern China.The North China Plain一a key corn-producing area in East China with a unique topography一was invaded by fall armyworm in 2019 and is seriously threatened by this migratory pest.However,the spatiotemporal extent of the migratory movements of fall armyworm from the North China Plain remains poorly understood.Using an air transport-based trajectory modeling approach that incorporates flight behavior,we simulated the potential nocturnal migration trajectories of fall armyworm from the North China Plain based on historical meteorological data from June to October of 2015-2019,and examined the night-time atmospheric conditions associated with their possible flights.The emigration patterns showed monthly variation in the main landing area and common migration direction.The displacement of newly emerged moths from the North China Plain was concentrated in the Northeast China Plain(including Liaoning,Jilin and Heilongjiang provinces)before late summer,after which they were most likely to undertake return flights to the south(especially into Hubei,Anhui and Hunan provinces).This southwest-northeast aerial migration corridor follows the topography of East China and is affected by the East Asian monsoon.These topographic-atmospheric conditions have resulted in the North China Plain becoming a key stopover for fall armyworm populations engaging in multigenerational long-distance migration across East China.These findings contribute to our knowledge of fall army-worm migration and will aid in the implementation of management and control strategies against this highly migratory agricultural pest.

Effects of neem-based insecticides on beet armyworm （Lepidoptera： Noctuidae）

Three commercial neem [Azadirachta indica A. Juss (Meliaceae)]-basedinsecticides, Agroneem, Ecozin, and Neemix, and a non-commercial neem leaf powder, were evaluatedfor oviposition deterrence, antifeedant effect on larvae, and toxicity to eggs and larvae of thebeet armyworm, Spodoptera exigua (Huebner) (Lepidoptera: Noctuidae), on cotton leaves in thelaboratory. Oviposition deterrence in no-choice, and two- and five-choice assays, was observed forthe neem-based insecticide treatments when compared with a non-treated control. Neem-basedinsecticides also deterred feeding by beet armyworm larvae. Direct contact with neem-basedinsecticides decreased the survival of beet army-worm eggs. Survival of beet armyworm larvae fed for7 days on leaves treated with neem-based insecticides was reduced to 27, 33, 60, and 61% for neemleaf powder, Ecozin, Agroneem, and Neemix, respectively. Possibilities for adoption of neem-basedinsecticides in commercial cotton for beet armyworm control are discussed.

Effects of DIMBOA on impulse discharges of maxillary lateral sensillum styloconicum of armyworm larvae

THE DIMBOA (2, 4-dihydroxy-7-methoxy-1, 4-benzoxazin-3-one), a secondary product present in corn plants, plays an important role in protecting the plant against the pest attack. DIMBOA is rich in seedlings of cereal crops, especially in maize. Many investigators demonstrated a linear relationship between the DIMBOA content in plant and the resistance of the plant to pest. Feng et al. (1992) summarized that the toxicity of DIMBOA is associated