Major Defoliator Research Articles

Common Moths and Their Ecological Importance in Bisra Range, Rourkela Forest Division, Odisha, India

Rourkela Forest Division presents a sub-tropical climatic condition with high humidity and rainfall after the onset of the monsoon. Lepidopterans are a group of insects that are potent pollinators and protectors of different terrestrial ecosystems. Among all the Lepidopterans, moths are cosmopolitan and very important. Moths are mostly nocturnal pollinators and play a vital role in the pollination of different plant species and their seed production. Besides that, they play the important role of both prey and predator in a food chain. They are less known and have always been given less importance, unlike bees and butterflies, because very few studies have been done about moths and their importance in ecosystems. A field survey was done for the documentation of some common moths’ diversity in Bisra Range, Rourkela Forest Division, Odisha, India, during 2022–2023. About 20 species of common moths were reported from the study area. This study depicts the ecological importance of moths, how they are inevitable members of the food chain in different types of terrestrial ecosystems, and their interactions with other plant and animal species in the division. Macrobrochis gigas and Phocoderma velutina larvae are abundant and major defoliators of Shorea robusta during the rainy season; Lymantria mathura is a major defoliator of Mangifera indica, Shorea robusta, Terminalia, Mitragyna, and Eugenia spp.; Xyleutes strix and Xyleutes persona are stem borers; and Phocoderma velutina shows a relationship with a parasitic fungus.

Seasonal occurrence of major defoliators of castor in Tamil Nadu

Castor is a non-edible oil bearing crop adapted to dry lands of tropics and semi-arid tropics. The seasonal occurrence of major defoliators viz., semilooper, Spodoptera and hairy caterpillars in castor was recorded continuously for last ten years (2012-2022) at Tapioca and Castor Research Station, Yethapur. The results revealed that Spodoptera litura was the major defoliator with a mean population of 4.3 larva/plant /year followed by semilooper and hairy caterpillar with 1.74 larva/plant/year and 1.44 larva/plant/year respectively. The maximum population of defoliators was recorded every year during 43rd to 49th standard weeks (October, November).

Efficacy of Cyclaniliprole 100 DC for the management of major defoliators in Soybean

The efficacy of newer insecticide molecule Cyclaniliprole 100 DC was evaluated against major insect pests of soybean during kharif 2020 and 2021. Among the different treatments, Cyclaniliprole 100 DC @ 40 g a.i/ha (400 ml/ha) was found to be effective and economical dose for the management of semilooper, spodoptera and girdle beetle pests in Soybean. It has recorded higher seed yield and found equally good with recommended insecticidal check. No phytotoxicity was observed on all the dosages of Cyclaniliprole 100 DC evaluated.

Management of major defoliators of soybean using microbial agents

Field experiment was conducted in kharif 2019-20 at AICRP on Soybean, V.N.M.K.V., Parbhani to evaluate the bioefficacy of different biopesticides along with control against major defoliators of soybean. Among the different treatments, after 2nd spray, at 7 DAT, microbial agent N. rileyi recorded significantly lowest of 0.58 larvae/mrl and found superior over rest of the microbial agents in reducing the population of semiloopers. However, it was found at par with the microbial agent B. bassiana (0.75 larvae/mrl). Next best microbial agents were treatment Bt (0.83 larvae/mrl) and M. anisopliae (1.00 larvae/mrl). The microbial agent treatment N. rileyi recorded highest of 1281 kg/ha yield. However, it was found at par with microbial agents treatment B. bassiana (1141 kg/ha) and Bt (1110 kg/ha).

Incidences of Heterocrasa expansalis (Insecta: Leipdoptera: Pyralidae) Attack on Quercus floribunda in Western Himalaya

Quercus floribunda (Green Oak) which is locally known as Moru Oak, is one of the important species of oaks widely distributed in the north western Himalayan ecosystems in the altitudinal range of 2000 to 2800m above msl. The Moru Oak is very vulnerable to insect pests attack and sometimes these attacks transformed into the outbreak of pests. During the study extensive surveys were carried out in the selected sites i.e. Chamba, Kullu and Shimla to assess the insect pest infestation during different seasons i.e. pre-monsoon, monsoon, post-monsoon using an appropriate design. During this study different insect pests attacking different parts (Leaves, stem, acorns etc.) of Moru Oak were observed along with the extent and frequency of insect attack. Insects were collected in the field and geo-information of the study sites was also recorded. The study on life history of a major defoliator Heterocrasa expansalis was undertaken in the laboratory. Assessment of the damage by different insect pests on Oak species was monitored and data on infestation status was recorded. Management of defoliators using IPM methods was also discussed.

Biological and biochemical effects of lufenuron on Xanthogaleruca luteola (Muller, 1766 ) (Coleoptera: Chrysomelidae)

Xanthogaleruca luteola (Mull., 1766) is the major defoliator pest of elm trees in urban area. In this study the effect of lufenuron on some biochemical and biological characteristics was investigated on X. luteola. The LC30 and LC50 of lufenuron were determined on the second instar larvae as 20.22 and 36.65 mg l-1, respectively. Effects of LC30 and LC50 concentrations of lufenuron on some biological parameters showed that lufenuron caused an increase in larval, pre-pupal and pupal developmental periods. Also, none of the female insects that emerged from the treated larvae did not spawn during their life. The LC50 concentration of lufenuron decreased carbohydrate, lipid and protein content and increased glycogen content. But there was not a significant difference in glycogen, and protein contents following the exposure to LC30 concentration. However, glutathione-s-transferase (GST) and esterase activities were significantly increased at LC50. In conclusion, due to lethal and sublethal effect of lufenuron on biochemical and biological traits of X. luteola, it can be recommended for control this pest in IPM program.

Insect fauna of soybean at different growing seasons: A comparative study

Present investigation was a field experiment to document the insect pests of soybean at different growth stages during rabi-summer season of 2020-21 and comparing them with the Kharif season pests in order to know the incidence pattern. Among sucking pests, leaf hoppers and thrips were causing considerable damage while whiteflies and aphids considered as minor during rabi and summer. Leaf miner and leaf folder were considered as major defoliators during rabi-summer which are replaced by Spodoptera litura and Bihar hairy caterpillar in Kharif. Among the pod borers Etiella zinckenella and Cydia ptychora were major and caused considerable damage during summer and Kharif, respectively. Stem fly was absent during early rabi while it was present in late rabi, Kharif and summer. The insect pest incidence spectrum varied in different growing seasons of soybean crop in this region.

Shorea robusta Gaertn.f : A review on its importance, entomological problems and management in the Indian sub-continent

Shorea robusta is an ecologically and economically important and dominant timber species in tropical forests of Indian sub-continent. Apart from strong, elastic and heavy heartwood timber, the coppice shoots of Sal are used for making household or agricultural implements and is a good source of firewood. Leaves are lopped for fodder and the flavonoids present in the leaves can be used as an active ingredient of several medicines. Additionally, the processed Sal seeds have a leading role in food and cosmetic sectors. The seed oil has become a significant foreign exchange earner for India. In India, Sal is one of the most affected species in terms of insect attack. Subsequently, insect damages, in varying degrees from seeds to finished products are the major reasons for decline in population of Sal forests. A total of 340 insect species belonging to 56 families under eight orders have been recorded that are associated with Sal in the country. About 145 insect species has been reported feeding on the green standing Sal trees which may be grouped as seed insects, nursery pests, defoliators, stem and root borers and sap suckers. Pammene theristis , for instance is responsible for heavy infestation of the seedlings and seeds of Sal. Major pest during nursery practice is Holotrichia consanguinea which lays eggs in the soil and grubs feed on the root system of the 2-3 years old seedlings of Sal. The major defoliators belong to the order Lepidoptera comprising of 93 species. Notably, Hoplocerambyx spinicornis , the most serious pest and a single species of heartwood borer of Sal is capable of attacking and killing healthy trees of any age and size. About 90 species of timber borers causes damage to Sal, of which six species feed on rotten logs or stumps. The current communication aims to provide a detailed account on different insect pests infesting Sal in India.

Multitype bistability and long transients in a delayed spruce budworm population model

Spruce budworm is a major defoliator of forests in North America and its periodic outbreak can cause severe economic growth loss. In 2008, Vaidya and Wu proposed a delayed spruce budworm population model and studied the impact of physiological structure on outbreak control (Vaidya and Wu, 2008 [27]). In this paper, we revisit this model and study its global dynamics that has not been analyzed previously. By carefully dealing with the major difficulty caused jointly by the time delay and the nonlinearity, we give a rather complete stability analysis for the model, including global asymptotic stability, bistability, semi-stability and Hopf bifurcation. Moreover, we show that the time delay can induce interesting dynamics including multitype bistability and long transients.

Ontogenetic Changes in the Behavioral Response to Light and Gravity in a Geometrid Larva

The hemlock looper, Lambdina fiscellaria, is a major defoliator of coniferous forests. As looper larvae are known for their wandering habits, we determined the underlying behavioral mechanisms that enable them to orient in the environment. First, we quantified the response of all larval stages to light or gravity, and to both stimuli tested simultaneously. Second, we evaluated the combined effect of substrate texture and light on the selection of pupation sites by wandering mature larvae (4th instar +10 days). We found that light attracted neonates and newly molted larvae of all stages, but response indices decreased significantly between the second and third larval stages. In a 45° inclined tube, larvae showed a geonegative response that remained relatively constant from one stage to the next. No synergy between the two stimuli was observed when a light source was placed on top of the inclined tube. In contrast, when the light source was placed at the base, the light signal dominated the gravity stimulus. Finally, wandering larvae were indifferent to unidirectional light and reacted positively to gravity. They preferred to pupate in a dark environment, a choice that could be modulated by positive photokinesis. Their final selection of a pupation site also involved physical contact with the substrate, which resembles positive thigmokinesis. The ecological significance of these results is discussed in relation to the spatial distribution of the various larval stages on host trees.

Population dynamics of major defoliators of rice

Population dynamics of major defoliators of rice

Efficacy of insecticides against major defoliators of rice

A field experiment carried out at the College of Agriculture, V C Farm, Mandya, Karnataka evaluated the efficacy of insecticides viz., indoxacarb 15.8EC @ 0.5 ml/l, flubendiamide 48SC @ 0.15 ml/l, chlorantraniliprole 18.5SC @ 0.12 ml/l, benfuracarb 3G @ 33 kg/ha, cartap hydrochloride 4G @ 25 kg/ha, fipronil 0.3G @ 25 kg/ha, acephate 75SP @ 1g/l and chlorpyriphos 20EC @ 2ml/l against major defoliators of rice viz., rice hispa, leaf folder, caseworm and horned caterpillar during kharif, 2018. The reduction of leaf damage over untreated control after imposing treatments was maximum with flubendiamide 48SC (56.99-82.72%) followed by cartap hydrochloride 4 G (52.24- 79.69%). Also, flubendiamide 48SC @0.15 ml/l was the most effective with maximum cost benefit ratio.

Pest categorisation of Leptinotarsa decemlineata.

The EFSA Panel on Plant Health performed a pest categorisation of the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae) for the EU. L. decemlineata is primarily known as a major defoliator of potatoes (Solanum tuberosum); feeding damage can result in significant yield loss. Field grown tomatoes and eggplants can be attacked and wild solanaceous species are also hosts. Having first established in Europe from North America in the early 20th century, L. decemlineata is now distributed in 21 EU Member States and is regulated in the EU by Commission Implementing Regulation 2019/2072, (Annex III) with protected zones in place for Cyprus, Ireland, Malta, Northern Ireland, parts of Spain (Ibiza and Menorca) and Portugal (Azores and Madeira), seven districts of Finland and five counties in Sweden. Adults occasionally enter some protected zones due to wind currents that carry flying adults; pathways are also provided by plant produce moved in trade. The availability of hosts and suitable climate make establishment of the pest possible in protected zones in the EU, especially in the southern EU. Spread within the protected zones could occur via adult flight and via leafy vegetables moved in trade. Impacts on potato yields would be expected within the protected zones; outdoor grown tomatoes and eggplants could be impacted in the protected zones of southern Member States too. Previous incursions into the current protected zones have been eradicated. L. decemlineata satisfies all of the criteria that are within the remit of EFSA to assess, to conclude that it is a potential protected zone quarantine pest. L. decemlineata does not satisfy all of the criteria that are within the remit of EFSA to assess with respect to regulated non‐quarantine pest status, specifically plants for planting are not the main means of spread.

Positive Results of an Early Intervention Strategy to Suppress a Spruce Budworm Outbreak after Five Years of Trials

Spruce budworm (Choristoneura fumiferana Clem.; SBW) outbreaks are one of the dominant natural disturbances in North America, having killed balsam fir (Abies balsamea (L.) Mill.) and spruce (Picea sp.) trees over tens of millions of hectares. Responses to past SBW outbreaks have included the aerial application of insecticides to limit defoliation and keep trees alive, salvage harvesting of dead and dying trees, or doing nothing and accepting the resulting timber losses. We tested a new ‘early intervention strategy’ (EIS) focused on suppressing rising SBW populations before major defoliation occurs, from 2014 to 2018 in New Brunswick, Canada. The EIS approach included: (1) intensive monitoring of overwintering SBW to detect ‘hot spots’ of low but rising populations; (2) targeted insecticide treatment to prevent spread; and (3) proactive public communications and engagement on project activities and results. This is the first attempt of area-wide (all areas within the jurisdiction of the province of New Brunswick) management of a native forest insect population. The project was conducted by a consortium of government, forest industry, researchers, and other partners. We developed a treatment priority and blocking model to optimize planning and efficacy of EIS SBW insecticide treatment programs. Following 5 years of over 420,000 ha of EIS treatments of low but increasing SBW populations, second instar larvae (L2) SBW levels across northern New Brunswick were found to be considerably lower than populations in adjacent Québec. Treatments increased from 4500 ha in 2014, to 56,600 ha in 2016, and to 199,000 ha in 2018. SBW populations in blocks treated with Bacillus thuringiensis or tebufenozide insecticide were consistently reduced, and generally did not require treatment in the subsequent year. Areas requiring treatment increased up to 2018, but SBW L2 populations showed over 90% reductions in that year. Although this may be a temporary annual decline in SBW population increases, it is counter to continued increases in Québec. Following 5 years of tests, the EIS appears to be effective in reducing the SBW outbreak.

Termination of pupal diapause in the pine processionary moth Thaumetopoea pityocampa

AbstractDiapause development is a complex process involving several eco‐physiological phases. Understanding these phases, especially diapause termination, is vital for interpreting the life history of many insect species and for developing suitable predictive models of population dynamics. The pine processionary moth is a major defoliator of pine and a vertebrate health hazard in the Mediterranean region. This species can display either univoltine or semivoltine development, with a pupal diapause extending from a few months to several years, respectively. Although the ecological and applied importance of diapause is acknowledged, its physiological regulation in either case remains obscure. In the present study, we characterize pre‐termination, termination and post‐termination phases of pupae developing as univoltine or remaining in prolonged diapause. Changes in metabolic activity are monitored continuously using thermocouples, comprising a novel method based on direct calorimetry, and periodically by use of O2 respirometry. The two methods clearly detect diapause termination in both types of pupae before any visible morphological or behavioural changes can be observed. Univoltine individuals are characterized by an increase in metabolic activity from pre‐termination through to termination and post‐termination, ultimately resulting in emergence. Remarkably, a synchronous termination is observed in individuals that enter prolonged diapause instead of emerging; however, in these pupae, the increased metabolic activity is only transient. The present study represents a starting point toward understanding the eco‐physiology of diapause development processes in the pupae of the pine processionary moth.

Negative cross-resistance between structurally different Bacillus thuringiensis toxins may favor resistance management of soybean looper in transgenic Bt cultivars

High adoption rates of single-gene Bacillus thuringiensis (Bt) Cry1Ac soybean impose selection pressure for resistance in the soybean looper, Chrysodeixis includens, a major defoliator in soybean and cotton crops. To anticipate and characterize resistance profiles that can evolve, soybean looper larvae collected from field crops in Brazil in 2013 were selected for resistance to Cry1Ac. Using two methods of selection viz., chronic exposure to Cry1Ac cotton leaves and the seven-day larval exposure to purified Cry1Ac on the artificial diet, 31 and 127-fold resistance was obtained in 11 and 6 generations of selection, respectively. The resistance trait had realized heritability of 0.66 and 0.72, respectively, indicating that most of the phenotypic variation in Cry1Ac susceptibility of the soybean looper larvae was due to additive genetic variation. The Cry1Ac-selected populations showed positive cross-resistance to Cry1Ab (6.7–8.7 fold), likely because these Bt toxins have a very similar molecular structure. Importantly, the Cry1Ac-selected populations became more susceptible to Cry2Aa and Cry1Fa, showing negative cross-resistance (up to 6-fold, P < 0.05). These results indicate that Cry1Ac, Cry1Fa, and Cry2A are compatible in a multi-toxin approach to minimize the risk of rapid adaptation of the soybean looper to Bt toxins.

Gypsy moth genome provides insights into flight capability and virus–host interactions

Since its accidental introduction to Massachusetts in the late 1800s, the European gypsy moth (EGM; Lymantria dispar dispar) has become a major defoliator in North American forests. However, in part because females are flightless, the spread of the EGM across the United States and Canada has been relatively slow over the past 150 years. In contrast, females of the Asian gypsy moth (AGM; Lymantria dispar asiatica) subspecies have fully developed wings and can fly, thereby posing a serious economic threat if populations are established in North America. To explore the genetic determinants of these phenotypic differences, we sequenced and annotated a draft genome of L. dispar and used it to identify genetic variation between EGM and AGM populations. The 865-Mb gypsy moth genome is the largest Lepidoptera genome sequenced to date and encodes ∼13,300 proteins. Gene ontology analyses of EGM and AGM samples revealed divergence between these populations in genes enriched for several gene ontology categories related to muscle adaptation, chemosensory communication, detoxification of food plant foliage, and immunity. These genetic differences likely contribute to variations in flight ability, chemical sensing, and pathogen interactions among EGM and AGM populations. Finally, we use our new genomic and transcriptomic tools to provide insights into genome-wide gene-expression changes of the gypsy moth after viral infection. Characterizing the immunological response of gypsy moths to virus infection may aid in the improvement of virus-based bioinsecticides currently used to control larval populations.

English

English

The impact of leaf-eating caterpillars (Heortia vitessoides) infestation on agar trees in Carita forest research station, Province of Banten

The gregarious caterpillars of Heortia vitessoides Moore is a major defoliator of agar trees. The pest seriously threatens the existing agar tree plantation that has been widely cultivated in the community. Pest attacks began to occur in Indonesia since 2005, resulting in the damage and death of agar tree plants in various regions.To determine the impact of pest attack, a study was conducted through periodic monitoring at agar plantation in Carita Forest Research Station (CFRS), Banten Province, from April 2012 to March 2015. Monitoring was conducted in three plots of agar plantations. Each plot consists of six permanent subplots and in each subplot 15 samples of agar tree were randomly choosen. Data were collected and analyzed on monthly basis according to the intensity of defoliation and the mortality of agar trees. Defoliation intensity was determined by the percentage number of trees suffering defoliation in four damage categories, i.e.: light (10-25%), moderate (25-50%), heavy (50-75%), and severe (75-100%). Tree mortality was calculated as the annual percentage of dead trees. The study showed that the defoliation occurred throughout the year in varying degrees of damage. The monthly percentage of defoliated trees is about 30-70% annualy. The high percentage of tree defoliation mainly occurs during dry and early rainy season (June-December). Higher percentage of heavy and severe defoliations were found mostly at seedling. Repeated heavy defoliation causes stunted growth and tree mortality. Early monitoring and control of pests are very important to be done regularly to prevent the damage wider and heavier.

Bottom-up factors contribute to large-scale synchrony in spruce budworm populations

Understanding the mechanisms that cause large-scale synchrony in insect population dynamics might yield key insights for predicting potential outbreak occurrence. Here, we evaluated which environmental factors best explain synchronous population fluctuations in the spruce budworm (Choristoneura fumiferana Clem.) (SBW), a major defoliator of coniferous forests in North America. SBW population levels were assessed with pheromone traps during the 1986–2014 period across a 625 000 km2 territory located in the province of Québec (Canada). The populations were characterized by abundance fluctuations that were often synchronized across the whole study area. Interannual population fluctuations were correlated with host tree cone production (a source of food) and high May temperatures, suggesting that synchrony was influenced by food availability and phenological mismatch during shoot development. Cone production was itself correlated with low precipitation during the previous summer. This study indicates that bottom-up trophic factors can drive spatiotemporal synchrony in insect populations and contribute to explain important and sustained population increases during some years. We also suggest that several biological processes, all influenced by weather, are likely to interact to explain population synchrony during the different phases of the approximately 35 year SBW outbreak cycle, complicating the prediction of climate change effects on this insect.