Response of Natural Enemies toward Selective Chemical Insecticides; Used for the Integrated Management of Insect Pests in Cotton Field Plots

Sucking pests are major threat to cotton field crop which cause unbearable losses to the crop yield. Aim of the current study was to record seasonal dynamics of major sucking insect pests including whitefly, jassid, thrips and their natural arthropod predators i.e. green lacewings and spiders in cotton field plots. The effects of surrounding field crops on pests' density and predatory efficiency of predators were also recorded. For sampling and survey of insects, the visual counting was found to be the most efficient method for recording the abundance of insects, trailed by net sweeping and tapping. Whitefly was the most dominant sucking pest found on the vegetative stage of cotton, followed by jassid and thrips. Fluctuated populations of predatory arthropods, spiders and green lacewings were also recorded during whole cropping season however, the densities of pests and predators varied with crop phenology. Spiders' population was encouraging at both vegetative and flowering stage and also the same trend of jassid and whitefly were observed at both stages of the crop. Surrounding habitats showed non-significant effect on population densities of insect pests and predators. For abiotic factors, the spiders showed strong positive correlation with humidity and temperature. However, green lacewing was only positively correlated with humidity. On the other hand, the populations of whitefly, jassid and thrips showed non-significant correlation with both temperature and humidity. Overall densities of sucking insect pests were found above economic threshold level. The plant age, crop stage and surrounding habitats effect on the population fluctuation of pests as well as the predators' abundance. The future studies are also warranted to investigate the altered habitats and multiple trap cropping to find out their impact on unattended insect predators and parasitoids in cotton crop.

The Efficiency of feeding stimulants (Bioenhencer) was studied alone and in combinations with chemical insecticides or entomopathogens against the defoliating pests, Spodoptera littoralis (Boisd.) and Spodoptera exigua Hbn. (in fields of cotton and soybean) and the bollworms Pectinophora gossypiella Saunders and Earias insulana Boisd. (in cotton field), at Kafr El-Sheikh governorate during the season 2003. Its adversely influence on the natural enemies associated these pests in the two fields, were also undertaken. Laboratory results indicated that the feed stimulant was exhibited at a high degree of efficiency against the target lepidopterous larvae when combined with the chemical insecticide and the bioinsecticides. But no obvious effect was found when it was used alone. Field results indicated that, the addition of Bioenhencer (5%) to the chemical and bio insecticides enhanced their activity, where the damaged rate significantly affected in these treated plots as compared to the untreated ones, on both cotton and soybean fields. Moreover, bioenhancer and the bioinsecticide had the least harmful effect on the entomophagous insect populations. Journal of Applied Sciences and Environmental Management Vol. 8 (2) 2004: 77-83

This field study evaluated marking both the pest [Helicoverpa zea (Boddie)] and its predator [Orius insidiosus (Say)] with rubidium chloride (RbCI) in corn to detect dispersal of these insects from this crop into sorghum and cotton. Sorghum and cotton were planted in small plots at the interface, or common boundary, of a commercial corn and cotton field. The cotton field adjacent to these interface plots was divided into cotton field plots. Foliar solutions of RbCI were applied to corn at field site 1 when the ears were infested with 4th through 6th instars of H. zea and at site 2 when corn silks were infested with eggs and 1st instars of H. zea and nymphs and adults of O. insidiosus. Insects were collected at various times after RbCI application from the sorghum interface plots, cotton interface plots, and cotton field plots. Both H. zea eggs and O. insidiosus females were successfully marked in corn treated with RbCI, and marking success for both insects ranged from 15–33%. Data on rubidium-marked insects indicated that H. zea females from the generation feeding on rubidium-treated corn dispersed into sorghum interface plots at both treated sites and into cotton interface plots at one site and that O. insidiosus females dispersed from corn into sorghum interface plots and cotton field plots at one site.

In the northwestern United States, insect pests of potatoes (Solanumtuberosum L.) have typically been controlled using broad-spectrum insecticides. However, the loss or impending loss of many broad-spectrum chemicals is increasing the use of selective insecticides, and organic potato production is growing in the region. In the 2001 and 2002 growing seasons, we intensively sampled the arthropods in 31 (14 in 2001 and 17 in 2002) production potato Þelds under three pest management regimens: conventional Þelds treated with broad-spectrum insecticides (Hard), conventional Þelds treated with selective insecticides (Soft), and organic Þelds treated with insecticides certiÞed for organic production (Organic). All Þelds were within the Columbia Basin of Washington, grown under center-pivot irrigation. We sampled arthropods using three techniques: D-vac suction sampling, pitfall trapping, and visual searching. Geocoris spp. and Nabis spp. bugs (Hemiptera) and spiders (Araneae) were the most abundant predators in plant foliage, together making up 90% of the foliar predator community in both years. Total predator densities and densities of Geocoris, Nabis, and spiders not in the family Linyphiidae were highest in Organic and Soft, and lowest in Hard Þelds. Linyphiid spider densities were marginally elevated in Soft compared with Hard Þelds. On the ground, carabid (Coleoptera: Carabidae) and staphylinid (Coleoptera: Staphylinidae) beetles and a diverse group of spiders dominated the community, together making up 90% of the ground-active predator com- munity in both years. Total predator densities and densities of carabid beetles, staphylinid beetles, and linyphiid spiders were highest in Organic and Soft and lowest in Hard Þelds, whereas densities of these arthropods did not differ between Organic and Soft. Densities of nonlinyphiid spiders were highest in Organic, intermediate in Soft, and lowest in Hard Þelds. While predator densities were generally high in organic Þelds, these Þelds also had the highest densities of the two most injurious insect pests, the green peach aphid (Myzus persicae Sulzer) and the Colorado potato beetle (Leptinotarsa decem- lineata Say). Selective insecticides allowed conventional growers to achieve predator densities similar to those seen in organic Þelds while retaining low pest densities typical of Þelds treated with broad-spectrum insecticides.

A 3-yr study evaluated tobacco as a trap crop for the tobacco budworm, Heliothis virescens (F.), in cotton. Small plot experiments were conducted on an experimental farm at Mississippi State University in Starkville, MS, in 1996 and on a commercial farm in Aliceville, AL, in 1997 to determine the ability of small strips of tobacco to trap H. virescens in cotton field plots. In the 1996 experiment, tobacco budworms eggs were significantly higher on tobacco than on cotton from 7 June through 19 June and from 10 July through 22 July. In 1997, H. virescens eggs were significantly higher on tobacco than on cotton for every sampling date throughout the growing season. The conclusion derived from these small plot experiments was that H. virescens females preferred tobacco over cotton as an ovipositional site. Therefore, in 1998, a large-scale field experiment was conducted to determine the effectiveness of tobacco as a trap crop for H. virescens in commercial cotton fields in Funston, GA. In this experiment, the number of H. virescens eggs was significantly lower in cotton fields with tobacco trap crops compared to control cotton fields without tobacco trap crops on 2 and 9 July. Also, economic threshold for H. virescens was not reached in these cotton fields with tobacco trap crops. In contrast, the economic threshold for this pest was met in cotton fields without tobacco trap crops on two dates during the growing season. For each year of the study, percentage total real mortality (rx) for eggs and larvae of H. virescens on tobacco was very high, ranging from 91.4–99.9%. Larval mortality was attributed in part to parasitization by Toxoneuron nigriceps (formerly Cardiochiles nigriceps) Viereck and Campoletis sonorensis Cameron and an infection by an ascovirus of H. virescens. Thus, tobacco served as a trap crop and sink for H. virescens in cotton in this study.

Integrated effects of plastic film residues on cotton growth and field carbon sequestration under drip irrigation in arid oasis regions

Green lacewing, Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) is a valuable bio-control agent that predates over various insect pests with high efficacy. It has developed considerable resistance to different classes of insecticides. This study was planned to investigate resistance level, stability and reversion rate against some new chemical insecticides using a field collected population of C. carnea. Field collected strain of C. carnea showed 313.44-fold, 216.50-fold and 276.83-fold resistance to imidacloprid, indoxacarb and chlorfenapyr compared to susceptible population, respectively. Baseline susceptibility values of C. carnea to imidacloprid, indoxacarb and chlorfenapyr were 2627.31, 502.10 and 581.89 ppm, while the insecticide resistance decrease rate was −0.039, −0.048 and −0.040, respectively. Rotation of these insecticides requires quality measures maintaining survival of C. carnea in an intense environment where repeated applications are required to avoid economic damage by pests.

Resistance of green lacewing, Chrysoperla carnea Stephens to nitenpyram: Cross-resistance patterns, mechanism, stability, and realized heritability

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In the United States, cotton leafroll dwarf disease, caused by cotton leafroll dwarf virus (CLRDV, Polerovirus, Luteoviridae), was first reported from cotton (Gossypium hirsutum L.) fields in Alabama (Avelar et al. 2019) and later Mississippi (Aboughanem-Sabanadzovic et al. 2019) and Georgia (Tabassum et al. 2019). During a survey of cotton fields in Barber County, Kansas, in the 2019 growing season, cotton plants showed virus-like symptoms including leaf yellowing, discoloration, reddening, and short internodes with reduced or small boll sets. Disease incidence based on virus-like symptoms was ∼1 to 15% depending on the affected fields. Eleven symptomatic and seven apparently asymptomatic leaf samples from 18 independent cotton plants (cv. PhytoGen 210) were collected in commercial cotton fields and tested for the presence of the virus in the Plant Virology Lab at the University of Tulsa, Oklahoma. Total RNA was extracted from all 18 samples by the Spectrum Plant Total RNA Kit (Sigma-Aldrich) and was synthesized into complementary DNA (cDNA) using the Superscript IV Reverse Transcription Kit (ThermoFisher Scientific) according to the manufacturer’s instructions. The polymerase chain reaction (PCR) was performed with primers CLRDV3675F and Pol3982R as described previously (Sharman et al. 2015) to amplify a specific PCR product of 310 bp of the ORF3-5 fragment of the CLRDV. cDNA of CLRDV for the specific fragment was obtained from the Plant Disease Diagnostic Lab at Auburn University and was used as a positive control. A PCR product of the predicted size (310 bp) was obtained from seven symptomatic cotton samples and the positive control, whereas no bands were present in four symptomatic and seven asymptomatic samples, as well as the PCR negative control. RT-PCR was repeated twice with these samples and obtained the same results as above. The PCR products of all positive samples were directly sequenced, and sequence comparison showed 97 to 99% identity with the CLRDV-Alabama isolate (MN071395). To further confirm the presence of CLRDV in these samples, two additional pair of primers—AL674F and AL1407R for partial P0/P1 (Avelar et al. 2019) and RdRpF2 and RdRpR1 for partial RdRp (Aboughanem-Sabanadzovic et al. 2019)—were used to amplify the 694- and 770-bp product of the CLRDV genome, respectively. The expected PCR bands were obtained from all seven symptomatic cotton plants but none from asymptomatic samples. PCR products of 694 and 770 bp from two samples (KS-7 and KS-10 isolates) were purified, cloned into pGEM-T Easy vector (Promega), and transformed into Escherichia coli DH5α cells (New England Bio Labs). At least three clones were sequenced using the Applied Biosystem 3130 Genetic Analyzer at the University of Tulsa. Sequences obtained in this study for partial P0/P1and RdRP genes of KS-7 and KS-10 isolates were deposited in GenBank (MN809925 to 28). Nucleotide sequence comparisons and BLASTn analysis of partial P1/P0 (MN809927 to 28) showed 98 to 99% identity with corresponding sequences of Alabama isolates (MH883237 and MN071395) and 92 to 93% identity with typical and 91 to 92% identity with atypical CLRDV isolates from Argentina and Brazil. Similarly, partial RdRP genes (MN809925 to 26) showed 94 to 98% identity with the corresponding sequences of available CLRDV isolates from Mississippi (MK512759, MK512762 to 64) and Alabama (MN071395) and 93 to 96% identity with typical and 92 to 95% identity with atypical CLRDV isolates from Argentina and Brazil. This is the first report of CLRDV infection and occurrence in cotton fields in Kansas. Cotton acreage in Kansas has increased since 2018 by 40% (NASS 2018), and the presence of CLRDV could be a detrimental disease for cotton production. Therefore, further studies are needed, including other cotton-growing counties in Kansas, to determine the distribution, epidemiology, vector transmission, and population structure of this virus, which would be helpful in the management of CLRDV.

Predatory arthropods can be important for preventing insect pests from reaching damaging levels in soybean. However, the predator community can be compromised when pest control strategies include the application of broad-spectrum insecticides. The use of selective insecticides such as diamides could conserve predators while still providing necessary pest control. We evaluated two selective diamide insecticides, chlorantraniliprole and flubendiamide, and a broad-spectrum insecticide, lambda-cyhalothrin in combination with chlorantraniliprole, for impact on predators in soybean. We applied insecticides to field plots and documented predator abundance prior to and up to 3 wk postapplication using sticky card, beat sheet, and sweep net sampling methods. In sweep net samples, total predator abundance in plots treated with the selective insecticides was not significantly different from untreated control plots. For beat sheet samples, there were no significant differences in the abundance of total predators on any day postapplication between the selective diamide insecticides or the untreated control, but abundance decreased after application of lambda-cyhalothrin + chlorantraniliprole and did not recover. For sticky cards, there were no differences in predator abundance among treatments on any day postapplication. Over all, results showed that there were no significant differences in the abundance of total predators, Anthocoridae, Araneae, or Geocoridae after application of flubendiamide or chlorantraniliprole compared with the untreated control for up to 3 wk after application. All insecticides significantly decreased populations of lepidopteran pests compared with the untreated control, but only lambda-cyhalothrin + chlorantraniliprole reduced predatory arthropod abundance.

Development of insect resistance to insecticide has been the major driving force for the development of new insecticides. Awareness and demand from public for more environmentally friendly insecticides have contributed in shifting the trend from using broad spectrum to selective insecticides. As a result, scientists have looked for new target sites beyond the nervous system. Insect growth regulators (IGRs) are more selective insecticides than conventional insecticides, and ecdysone agonists are the newest IGRs being commercialized, e.g. tebufenozide, methoxyfenozide, and halofenozide. Ecdysone agonists bind to the ecdysteroid receptors, and they act similarly to the molting hormone 20-hydroxyecdysone. The binding provides larvae or nymphs with a signal to enter a premature and lethal molting cycle. In addition, the ecdysone agonists cause a reduction in the number of eggs laid by female insects. The ecdysone agonists are being developed as selective biorational insecticides. Tebufenozide and methoxyfenozide are used to control lepidopteran insect pests, whereas halofenozide is being used to control coleopteran insect pests. Their selectivity is due to differences in the binding affinity between these compounds to the receptors in insects from different orders. The selectivity of these compounds makes them candidates to be used in combinations with other control strategies to develop integrated pest management programs in agricultural ecosystems.

This study was conducted to investigate weed infestations of cotton (Gossypium hirsutum) fields in the region of Tarim River. Forty‐nine species among 17 families were identified in these cotton fields, and 24 of them were annuals. The eight dominant weed species in the cotton fields of Tarim River basin included Chenopodium glaucum, Solanum nigrum, Chenopodium album, Chenopodium hybridum, Bolboschoenus planiculmis, Sonchus arvensis, Phragmites australis, and Mulgedium tataricum. The number of weed species in the Aksu River tributary area, Yeerqiang River tributary area, and the upper and lower reaches of the Tarim River reached 29, 36, 35, and 33, respectively. Twenty species were found widely distributed among each basin. The dominant weeds in the cotton fields in the Aksu River basin and upper reaches of the Tarim River were S. nigrum and C. glaucum, those in the cotton fields in the Yarkand River basin included C. album and C. hybridum, and those in the cotton fields in the lower reaches of the Tarim River were C. glaucum and C. album. Notably the 20 common surveyed species of C. glaucum, S. nigrum, C. album, C. hybridum, B. planiculmis, S. arvensis, P. australis, M. tataricum, and others, could pose a serious challenge to regional crop production if not adequately controlled. As such, each cotton field should adopt a suitable weeding scheme with strengthened weed monitoring according to the local conditions, especially the weed distribution area characteristics.

Selective tools, including selective insecticides and transgenic cotton, have been crucial in reducing insecticide usage within the integrated pest management (IPM) plan for Arizona cotton. To guide growers effectively, cotton field trials evaluated the effects of the novel insecticides, isocycloseram and afidopyropen against our primary pests, Bemisia argentifolii and Lygus hesperus, and their impacts on nontarget arthropods, including key predators: Collops spp., Orius tristicolor, Geocoris spp., Misumenops celer, Drapetis nr. divergens and Chrysoperla carnea s.l. Assessments involved over 27 arthropod taxa through community analyses, individual predator abundance, and biological control function via predator to prey ratios and a sentinel prey method. Comparisons were made with an untreated check, a proven fully selective insecticide (flonicamid) and acephate-treated positive controls. Overall, relative to the untreated check, afidopyropen showed no significant differences, whereas isocycloseram exhibited some negative impacts, primarily reducing M. celer and Geocoris spp. nymphs, yet it was less detrimental compared with the positive control, acephate, and it did not affect four of the six key predators and most nontarget arthropods. Afidopyropen was classified as a fully selective insecticide and isocycloseram as a partially selective insecticide. Their fit for conservation biological control in Arizona cotton IPM and similar systems is discussed. © 2024 Society of Chemical Industry.

The Asian citrus psyllid (ACP) Diaphorina citri Kuwayama vectors pathogens that cause huanglongbing (HLB) or citrus greening devastating and economically important disease present in most citrus growing regions. Young citrus shoots are required for psyllid reproduction and development. During winter citrus trees produce little or no new growth. Overwintering adults reproduce in spring on newly emerging shoots also attractive to other pests and beneficial insects. Botanicals and relatively selective insecticides could help to conserve beneficial insects and reduce pest resistance to insecticides. Sprays of Azadirachtin (Neem), Tropane (Datura), Spirotetramat, Spinetoram, and broad-spectrum Imidacloprid were evaluated to control ACP in spring and summer on 10-year-old "Kinow" Citrus reticulata Blanco trees producing new growth. Psyllid populations were high averaging 5-9 nymphs or adults per sample before treatment application. Nymphs or adults were significantly reduced to 0.5-1.5 per sample in all treatments for 3 weeks, average 61%-83% reduction. No significant reduction in ladybeetles Adalia bipunctata, Aneglei scardoni, Cheilomenes sexmaculata, and Coccinella septempunctata was observed. Syrphids, spiders and green lacewings were reduced in treated trees except with Tropane. Studies are warranted to assess impact of these predators on ACP and interaction with insecticides. Observed reduction in ACP populations may not be enough considering its reproductive potential and role in the spread of HLB. Follow-up sprays may be required to achieve additional suppression using rotations of different insecticides.