Aphid Management Research Articles

Impact assessment of plant protection technologies validated/ demonstrated by KVK, Angul (Odisha) during 2002-2009

A good number of agro technologies have been assessed and demonstrated in the farmers’ field by KVK, Angul during 2002-2009. Impactassessment of plant protection technologies revealed that the technologies are being adopted by the farmers at variable rate over time. Highest adoption rate (65%) was observed with application of Acephate 75 per cent SC twice @ 0.2 per cent at 15 days interval for management of aphid in mustard with horizontal expansion to 382 ha area. On the other hand lower adoption rate (6%) was observed for the technology of release of bio-agent Chrysoperla cornea for management of this insect pest. The IPM technology consisting of removal of affected fruits and shoots followed by alternate spraying of Triazophos@ 0.2 per cent and neem oil @ 0.5 per cent with teepol at 15 days interval for management of shoot and fruit borer was found to be adopted by 52 per cent participants with horizontal spread to 264 ha of additional area. Non-availability of inputs and seeds of high yielding variety of crops, delay in input availability, non-availability of resistant variety, inadequate supply of inputs and poor quality of inputs, non-availability of skilled labours ,high cost of labour and lack of credit facility are the major constraints for low adoption of these technologies. These constraints need to be addressed systematically to improve the adoption percentage of these technologies. How to view point the article : Das, Niranjan and Mishra, R.P. (2016). Impact assessment of plant protection technologies validated/demonstrated by KVK, Angul (Odisha) during 20022009. Internat. J. Plant Protec., 9(1) : 252-255.

Effects of spirotetramat treatments on fecundity and carboxylesterase expression of Aphis gossypii Glover.

Spirotetramat is a novel tetramic acid-based insecticide, belonging to keto-enol pesticide family, with a novel mode of action; it interferes with lipid biosynthesis. Its insecticide activity against various agricultural pest insects have been demonstrated (e.g. on Myzus persicae, Bemisia tabaci and Tetranychus urticae). However, information available is currently limited on the efficacy of spirotetramat on the cotton aphid, Aphis gossypii, a key cotton pest worldwide. We assessed the spirotetramat toxicity on A. gossypii and evaluated its effects on aphid fecundity when exposed to a sublethal concentration (LC10) and to increasing lethal concentrations (LC25, LC50, and LC75). A key mechanism involved in insecticide resistance in aphids relates to esterase activity. We estimated the CarE activity and a CarE gene expression in aphids in response to spirotetramat exposure, then we tested tolerance of offspring to spirotetramat when the parents were exposed to the highest concentration tested in our study (LC75). Results showed that spirotetramat showed increasing toxicity to A. gossypii with exposure duration to treated leaves; LC50 ranged from 23,675.68 to 12.27mg/L for 1 to 5-days exposure. In addition, spirotetramat reduced aphid daily fecundity, in all concentration treatments, especially with up to 90% reduction in case of exposure to LC75. Total CarE activity increased dramatically and CarE mRNA expression was also up regulated in aphids after exposure to LC75 spirotetramat. Finally, the tolerance to spirotetramat in offspring (when parents were exposed to the LC75) showed a 2.5-fold increase when compared to control aphids. Consequently, spiroteramat showed potential for pest management of cotton aphids owing to both lethal and sublethal activities, notably strong impact on aphid fecundity. However, we also demonstrated that increased tolerance of A. gossypii to spirotetramat may happen through increased CarE- activity and subsequent metabolic degradation of the insecticide in aphids' body.

Virulent Diuraphis noxia Aphids Over-Express Calcium Signaling Proteins to Overcome Defenses of Aphid-Resistant Wheat Plants.

The Russian wheat aphid, Diuraphis noxia, an invasive phytotoxic pest of wheat, Triticum aestivum, and barley, Hordeum vulgare, causes huge economic losses in Africa, South America, and North America. Most acceptable and ecologically beneficial aphid management strategies include selection and breeding of D. noxia-resistant varieties, and numerous D. noxia resistance genes have been identified in T. aestivum and H. vulgare. North American D. noxia biotype 1 is avirulent to T. aestivum varieties possessing Dn4 or Dn7 genes, while biotype 2 is virulent to Dn4 and avirulent to Dn7. The current investigation utilized next-generation RNAseq technology to reveal that biotype 2 over expresses proteins involved in calcium signaling, which activates phosphoinositide (PI) metabolism. Calcium signaling proteins comprised 36% of all transcripts identified in the two D. noxia biotypes. Depending on plant resistance gene-aphid biotype interaction, additional transcript groups included those involved in tissue growth; defense and stress response; zinc ion and related cofactor binding; and apoptosis. Activation of enzymes involved in PI metabolism by D. noxia biotype 2 aphids allows depletion of plant calcium that normally blocks aphid feeding sites in phloem sieve elements and enables successful, continuous feeding on plants resistant to avirulent biotype 1. Inhibition of the key enzyme phospholipase C significantly reduced biotype 2 salivation into phloem and phloem sap ingestion.

Ecologically Sustainable Pest Management for Thrips and Aphids in Groundnut

Two field experiments were conducted in groundnut for the management of aphids and thrips in an ecologically sustainable manner during 2014 - 15 at Agricultural Research Station, Bhavanisagar. The results showed that seed treatment with imidacloprid 70 FS 5 ml/kg followed by spraying with thiamethoxam 25 WG at 0.4 ml/l at 30 DAS (or) seed treatment with imidacloprid 70 FS at 5 ml/kg of seed followed by spraying with neem seed kernel extract (NSKE) 5% at 30 DAS + placing yellow sticky trap at 25/ha. at 30 DAS+ raising cow pea as trap crop+ release of green lace wing predator Chrysoperla zastrowi at 30 DAS @ 2500 / ha. (or) spraying neem oil 2% at weekly interval from 20 DAS five times (or) basal application of neem cake @ 250 kg/ha.+ placing yellow sticky trap @ 25/ha. at 20 DAS+ release of green lace wing predator C. zastrowi @ 2500 /ha. at 20 DAS+ Azadirachtin 1% spray at 2 ml/l. at 30 DAS + raising cow pea as trap crop/ cumbu as intercrop recorded significantly lower population of thrips and aphids along with higher pod yield. These pest management approaches are useful in formulating ecologically sustainable biointensive IPM strategies.

Foliar Application of Insecticides for Soybean Aphid Management in South Dakota, 2015: Table 1

Foliar Application of Insecticides for Soybean Aphid Management in South Dakota, 2015: Table 1

Soybean Aphid Efficacy Screening Program, 2015

Soybean aphid, Aphis glycines Matsumura, has drastically changed soybean pest management in the North Central region. To date, SBA can be successfully managed by timely scouting and foliar insecticides. Host plant resistance is the newest soybean aphid management tool and is complementary to existing chemical control. In 2015, we established plots at two Iowa State University Research Farms (Northeast and Northwest) on 27 May and 27 May, respectively. NK S25-E5 soybean variety was used for all the soybean aphid-susceptible treatments, and 28ARC5 soybean variety was used for the Rag2 -containing treatments. Plots were arranged in an RCB design with four replications. Each plot was six rows in width and 50 ft in length at the Northeast location and six rows in width by 44 ft in length at the Northwest location. Treatments containing …

Detection of DNA in Aphid Honeydew: A Source of Error for Molecular Gut Content Analysis?

Abstract Aphids (Hemiptera: Aphididae) are pests of a vast array of crops globally, contributing to significant yield loss annually. Biological control, utilizing natural enemies to suppress focal pest species, has often been integrated into aphid management practices. To ensure that arthropod predators are consuming the target aphid, and ultimately have an impact on pest population dynamics, it is important to gather information on consumption patterns in space and time. Molecular gut content analysis can be used to assess the strength of trophic linkages between predators and prey by detecting the presence of species-specific DNA (including aphid DNA) in their gut. However, many generalist predators readily consume aphid honeydew as an additional nutritive resource beyond direct consumption of prey. This raises the important question of whether aphid honeydew is responsible for false-positive predation events being recorded using DNA-based gut content analysis, should honeydew contain detectable quantit...

Soybean Aphid Management in South Dakota with Foliar Applied Insecticdes, 2014: Table 1

The Soybean aphid, Aphis glycines Matsumura, can be a serious problem of soybean, Glycine max L., production in South Dakota. The economic threshold is 250 soybean aphids on 80% of plants sampled. When the threshold is reached it may warrant an insecticide treatment to prevent potential yield loss through early R5 soybean development stage. During the 2014 growing season, we conducted a field study near Brookings, South Dakota using foliar applied insecticides for control …

Integrated management of cotton aphid, Aphis gossypii on roof-planted eggplant, Solanum melongena

Prevalence and integrated management of cotton aphid, Aphis gossypii Glover (Homoptera: Aphididae) were studied on four varieties of roof planted eggplant (Solanum melongena L.) Along the sixteen weeks study period highest incidence of aphids (1959.17.17±172.44/plant) on eggplant variety of Blackboy were recorded at 16th week (last week of February, 2013) and the lowest incidence (12.83±8.68/plant) was recorded on the eggplant variety Singnath at 13th week (first week of February, 2013). The treatment having combination of 2g Neem seed kernel extract (NSKE) + ½gm detergent+100ml water) was most effective followed by a treatment of 2g NSKE+100ml water and 1g NSKE+100ml water in reducing the rate of aphid infestation. Eggplant variety Green round showed comparatively higher resistance in all aspects (from leaf and fruit infestation) followed by variety Muktakeshi and Black boy.Bangladesh J. Zool. 43(1): 19-26, 2015

Soybean Aphid Efficacy Screening Program, 2014

Soybean aphid, Aphis glycines Matsumura, has drastically changed soybean pest management in the North Central region. To date, SBA can be successfully managed by timely scouting and foliar insecticides. Host plant resistance is the newest soybean aphid management tool and is complementary to the existing chemical control. In 2014, we established plots at two Iowa State University Research Farms (Northeast and Northwest) on 24 May and 22 May, respectively. NK S25-E5 soybean variety was used for all the soybean aphid-susceptible treatments, and LD09-05484A soybean variety was used for the Rag1 -containing treatments. Plots were arranged in an RCB design with four replications. Each plot was six rows in width and 50 ft in length. Treatments containing a …

Interactions among vegetable-infesting aphids, the fungal pathogen Metarhizium anisopliae (Ascomycota: Hypocreales) and the predatory coccinellid Cheilomenes lunata (Coleoptera: Coccinellidae)

Entomopathogenic fungi are among biocontrol agents being considered for the control of aphids on a variety of crops. Predatory coccinellids, although generalist, are also among important natural enemies that must be conserved for aphid management. Laboratory studies were carried out to investigate the interaction between three vegetable-infesting aphids, Metarhizium anisopliae isolate ICIPE 62 and the coccinellid predator Cheilomenes lunata. At a concentration of 1 × 108 conidial ml–1, the fungus was found to cause mortality of 7.5% to C. lunata, compared to 2.5% mortality in the control at 10 days post-treatment. Female adult C. lunata to which fungus-infected aphids were offered as prey never accepted them as food source in non-choice bioassays. However, live and dead non-infected aphids were fed upon. In choice bioassay, a total of 1–3 out of 24 infected non-sporulating aphids per species (average of 0.1–0.4 aphids per arena) were consumed by 48 h-starved C. lunata within a period of 60 min, but avoided sporulating cadavers. Foraging adult C. lunata enhanced the spread of conidia of M. anisopliae from infected cadavers to fourth instars Aphis gossypii feeding on okra (0.8–15.0% mortality), Brevicoryne brassicae (3.3–15.0% mortality) and Lipaphis pseudobrassicae (0.8–14.2% mortality) on kale plants. Results of this study demonstrate compatibility between M. anisopliae and C. lunata, and could provide a sustainable strategy for effective management of aphids on crucifers and okra cropping systems.

Effects of imidacloprid and clothianidin seed treatments on wheat aphids and their natural enemies on winter wheat

Wheat aphid (Hemiptera: Aphididae) is one of the major pests of winter wheat and has posed a significant threat to winter wheat production in China. Although neonicotinoid insecticidal seed treatments have been suggested to be a control method, the season-long efficacy on pests and the impact on their natural enemies are still uncertain. Experiments were conducted to determine the efficacy of imidacloprid and clothianidin on the control of aphids, the number of their natural enemies and the emergence rate and yield of wheat during 2011-2014. Imidacloprid and clothianidin seed treatments had no effect on the emergence rate of winter wheat and could prevent yield losses and wheat aphid infestations throughout the winter wheat growing season. Furthermore, their active ingredients were detected in winter wheat leaves up to 200 days after sowing. Imidacloprid and clothianidin seed treatments had no adverse effects on ladybirds, hoverflies or parasitoids, and instead increased the spider-aphid ratios. Wheat seeds treated with imidacloprid and clothianidin were effective against wheat aphids throughout the winter wheat growing season and reduced the yield loss under field conditions. Imidacloprid and clothianidin seed treatments may be an important component of the integrated management of wheat aphids on winter wheat. © 2015 Society of Chemical Industry.

Expressing p20 hairpin RNA of Citrus tristeza virus confers Citrus aurantium with tolerance/resistance against stem pitting and seedling yellow CTV strains

The Citrus tristeza virus (CTV) uses 3 silencing suppressor genes, p20, p23 and p25, to resist the attacks from its Citrus hosts. Inactivating these genes is therefore obviously a potential defensive option in addition to the current control strategies including aphid management and the use of mild strain cross protection. In this study, we cloned partial DNA fragments from the three genes, and used them to construct vectors for expressing hairpin RNAs (hpRNAs). To facilitate the formation of hpRNAs, the constructs were introduced in a loop structure. Following transformation of sour orange (Citrus aurantium) with these constructs, 8 p20 hpRNA (hp20) and 1 p25 hpRNA (hp25) expressing lines were obtained. The 7 hp20 transgenic lines were further characterized. Their reactions to CTV were tested following inoculation with CT14A and/or TR-L514, both of which are severe strains. Results showed that 3 lines (hp20-5, hp20-6 and hp20-8) were completely resistant to TR-L514 under greenhouse conditions for no detectable viral load was found in their leaves by PCR. However, they exhibited only partial suppression of TR-L514 under screen house conditions since the virus was detected in their leaves, though 2 months later compared to non-transgenic controls. Further tests showed that hp20-5 was tolerant also to CT14A under screen house conditions. The growth of hp20-5 was much better than others including the controls that were concurrently challenged with CT14A. These results showed that expressing p20 hpRNA was sufficient to confer sour orange with CTV resistance/tolerance.

Soybean Aphid (Hemiptera: Aphididae) Affects Soybean Spectral Reflectance.

Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is the most economically important insect pest of soybean in the north central United States. Scouting-based integrated pest management (IPM) programs could become more efficient and more widely adopted by using plant spectral reflectance to estimate soybean aphid injury. Our objective was to determine whether plant spectral reflectance is affected by soybean aphid feeding. Field trials were conducted in 2013 and 2014 using caged plots. Early-, late-, and noninfested treatments were established to create a gradient of soybean aphid pressure. Whole-plant soybean aphid densities were recorded weekly. Measurements of plant spectral reflectance occurred on two sample dates per year. Simple linear regression models were used to test the effect of cumulative aphid-days (CAD) on plant spectral reflectance at 680 nm (RED) and 800 nm (NIR), normalized difference vegetation index (NDVI), and relative chlorophyll content. Data indicated that CAD had no effect on canopy-level RED reflectance, but CAD decreased canopy-level NIR reflectance and NDVI. Canopy- and leaf-level measurements typically indicated similar plant spectral response to increasing CAD. CAD generally had no effect on relative chlorophyll content. The present study provides the first documentation that remote sensing holds potential for detecting changes in plant spectral reflectance induced by soybean aphid. The use of plant spectral reflectance in soybean aphid management may assist future IPM programs to reduce sampling costs and prevent prophylactic insecticide sprays.

FIELD EFFICACY OF INSECTICIDES IN THE MANAGEMENT OF POMEGRANATE APHID, APHIS PUNICAE (PASSERINI)

Field evaluation of new insecticide molecules for the management of pomegranate aphid, Aphis punicae was carried out at Bijapur-Karnataka for two years during 2010 and 2011. The study revealed that, among the different insecticide molecules, thiamethoxam 25 WG at 0.2 g/L recorded highest reduction in aphid population after both spray intervals followed by Imidacloprid 70 WG at 0.3 g/L. During the first year, the mean reduction in aphid population with thiamethoxam was 90.19 and 94.10% after the first and second spay, whereas during the second year, the reduction was to the extent of 91.19 and 93.42%, respectively. Similarly, during 2010, imidacloprid recorded 87.92 and 90.39% reduction in aphid population after first and second sprays whereas during 2011 it was 89.73 and 93.42%. The trees sprayed with thiamethoxam (9105 kg/ha) and imidacloprid (9038 kg/ha) have recorded highest quantity of marketable pomegranate fruits. Thiamethoxam and imidacloprid recorded highest gross returns, net returns and maximum B:C ratio during both the years of investigation.

Assessment of Sublethal and Transgenerational Effects of Pirimicarb on the Wheat Aphids Rhopalosiphum padi and Sitobion avenae.

The wheat aphids, Rhopalosiphum padi (Linnaeus) and Sitobion avenae (Fabricius), are key pests on wheat crops worldwide. Management practices rely primarily on insecticides. The pirimicarb (carbamate) is used extensively as an effective insecticide to control these two aphids. In addition to the mortality caused by pirimicarb, various sublethal effects may occur in aphids when exposed to low lethal or sublethal doses. Understanding the general effect of pirimicarb on aphids could help increasing rational use of this insecticide. Under laboratory conditions, we assessed the sublethal effects of a low lethal concentration of pirimicarb (LC25) on biological traits and acetylcholinesterase (AChE) activity of R. padi and S. avenae. Both direct and transgenerational effects, i.e. on parent and the F1 generations were assessed, respectively. We found that R. padi and S. avenae responded differentially to the LC25 of pirimicarb. The parent generation of R. padi showed a 39% decrease in fecundity and multiple transgenerational effects were observed in the F1 generation; overall juvenile development, reproductive period, adult longevity and lifespan were longer than those of the control group. By contrast, LC25 of pirimicarb showed almost no effects on S. avenae biological traits in both the parent and F1 generations; only the pre-reproductive duration was reduced in F1 generations. Demographic parameter estimates (e.g. rm) showed similar trend, i.e. significant negative effect on R. padi population growth and no effect on S. avenae. However, AChE activity decreased in both R. padi and S. avenae treated by the LC25 of pirimicarb. We demonstrated sublethal and transgenerational effects of pirimicarb in the two wheat aphid species; it hinted at the importance of considering sublethal effects (including hormesis) of pirimicarb for optimizing Integrated Pest Management (IPM) of wheat aphids.

Compatibility of flonicamid and a formulated mixture of pyrethrins and azadirachtin with predators for soybean aphid (Hemiptera: Aphididae) management

The invasive soybean aphid, Aphis glycines Matsumura, is an important pest in North American soybean production. Predators can play an important role in suppressing A. glycines. However, current A. glycines management practices rely primarily on broad-spectrum insecticides, which can adversely affect natural enemy populations. An alternative is the use of selective insecticides that control the targeted pest species, while having a reduced impact on natural enemies. In greenhouse and laboratory assays, we tested the effects of lambda-cyhalothrin, two rates of flonicamid, which is currently not registered for use in soybean, and a formulated mixture of pyrthrins and azadirachtin on A. glycines and its natural enemies, Chrysoperla rufilabris (Burmeister), Orius insidiosus (Say) and Hippodamia convergens (Guerin-Meneville). All insecticides significantly reduced A. glycines populations. Lambda-cyhalothrin was highly toxic to the natural enemies tested. Flonicamid showed the lowest toxicity to natural enemies, but the high rate did decrease survival of O. insidiosus. The mixture of pyrethrins and azadirachtin was toxic to larvae of C. rufilabris and adult O. insidiosus. Moreover, the mixture of pyrethrins and azadirachtin increased the developmental time of C. rufilabris. These results indicate potential for flonicamid and the mixture of pyrethrins and azadirachtin to increase compatibility between chemical and biological controls.

Potential Overwintering Locations of Soybean Aphid (Hemiptera: Aphididae) Colonizing Soybean in Ohio and Wisconsin.

Soybean aphids, Aphis glycines Matsumura, depend on long-distance, wind-aided dispersal to complete their life cycle. Despite our general understanding of soybean aphid biology, little is explicitly known about dispersal of soybean aphids between winter and summer hosts in North America. This study compared genotypic diversity of soybean aphids sampled from several overwintering locations in the Midwest and soybean fields in Ohio and Wisconsin to test the hypothesis that these overwintering locations are sources of the soybean colonists. In addition, air parcel trajectory analyses were used to demonstrate the potential for long-distance dispersal events to occur to or from these overwintering locations. Results suggest that soybean aphids from overwintering locations along the Illinois-Iowa border and northern Indiana-Ohio are potential colonists of soybean in Ohio and Wisconsin, but that Ohio is also colonized by soybean aphids from other unknown overwintering locations. Soybean aphids in Ohio and Wisconsin exhibit a small degree of population structure that is not associated with the locations of soybean fields in which they occur, but that may be related to specific overwintering environments, multiple introductions to North America, or spatial variation in aphid phenology. There may be a limited range of suitable habitat for soybean aphid overwintering, in which case management of soybean aphids may be more effective at their overwintering sites. Further research efforts should focus on discovering more overwintering locations of soybean aphid in North America, and the relative impact of short- and long-distance dispersal events on soybean aphid population dynamics.

Rag Virulence Among Soybean Aphids (Hemiptera: Aphididae) in Wisconsin.

Soybean aphid, Aphis glycines Matsumura, a pest of soybean, Glycine max (L.) Merr., and native of Asia, invaded North America sometime before 2000 and rapidly became the most significant insect pest of soybean in the upper Midwest. Plant resistance, a key component of integrated pest management, has received significant attention in the past decade, and several resistance (Rag) genes have been identified. However, the efficacy of Rag (Resistance to Aphis glycines) genes in suppressing aphid abundance has been challenged by the occurrence of soybean aphids capable of overcoming Rag gene-mediated resistance. Although the occurrence of these Rag virulent biotypes poses a serious threat to effective and sustainable management of soybean aphid, little is known about the current abundance of biotypes in North America. The objective of this research was to determine the distribution of Rag virulent soybean aphids in Wisconsin. Soybean aphids were collected from Wisconsin during the summers of 2012 and 2013, and assayed for Rag1, Rag2, and Rag1+2 virulence using no-choice tests in a greenhouse. One clone from Monroe County in 2012 reacted like biotype 4, three clones in different counties in 2013 responded like biotype 2, and eight others expressed varying degrees of Rag virulence. Rag virulence in 2013 was observed in aphids from 33% of the sampled sites and was accounted for by just 4.5% of sampled clones, although this is likely a conservative estimate. No-choice test results are discussed in light of current questions on the biology, ecology, and population genetics of soybean aphid.

Evaluation of petroleum spray oil against turnip aphid, Lipaphis erysimi (Kaltenbach) infesting oilseed brassica

Petroleum spray oil was evaluated against turnip aphid, Lipaphis erysimi (Kaltenbach) on Brassica juncea cv. PBR 210 at Punjab Agricultural University, Ludhiana during 2009–10 and 2010–11 crop seasons. Different treatments of petroleum spray oil included: 0.50, 0.75, 1.00, 1.25, 1.50 and 1.75% along with dimethoate 30 EC @ 1 lt ha−1 and untreated control. All the treatments resulted in significant reduction in the aphid population after 3 days of spray except petroleum spray oil (0.5%) and remained effective for up-to 10 days. Though, the chemical insecticide dimethoate was the most effective, petroleum spray oil @ 1.75% was statistically at par with it with 82.2–86.9% reduction in the aphid population and consistently remained effective for up to 10 days after application. Further, petroleum spray oil at either of the concentrations did not result in any toxic effect on Coccinella septempunctata and honey bees. The seed yield in the case of petroleum spray oil at all the concentrations, except at 0.5%, was statistically at par with the chemical insecticide dimethoate (1 lt ha−1) in 2009–10, however, in 2010–11, the yield differences were non-significant due to low aphid population. Keeping in view its efficacy, petroleum spray oil has the potential to be used as an alternative to chemical insecticides for the management of turnip aphid.