Control Of Thrips Research Articles

Asymmetric Synthesis and Biological Activity of Contact Pheromone of Western Flower Thrips, Frankliniella occidentalis

Western flower thrips, Frankliniella occidentalis, is a serious worldwide pest of agriculture and horticulture, and its contact pheromone is 7-methyltricosane. Two enantiomers of 7-methyltricosane were synthesized for the first time. The centra of our strategy were chiral auxiliaries to introduce stereocenter, and Wittig coupling to connect two blocks. The overall yields of our synthesis were 29–30% with seven steps. The electroantennogram (EAG) and the contact behavioral responses revealed that (R)-, (S)- and racemic 7-methyltricosane were separately bioactive, and the racemate was the most bioactive in the male arrestant activity and the female EAG test. This result provides valuable insights, showing that the racemate could be used for the support of the control of western flower thrips, which could be more easily prepared relative to more expensive enantiopure pheromone.

Possibility for control with botanical insecticides against the mealy plum aphid Hyalopterus pruni Geoffroy, 1762 (Hemiptera: Aphididae) on the plum in Southern Bulgaria

The aim of this study was to evaluate the efficacy of botanical insecticides recommended for control of the mealy plum aphid Hyalopterus pruni (Hemiptera: Aphididae). The experiment was carried out in 2024 in the experimental field of the Fruit Growing Institute-Plovdiv, Bulgaria. The tested insecticides were orange oil (Limocid), liquid extract of Urtica spp. (Basictec) and pyrethrins (Abanto). The insecticides were applied at the recommended concentrations for control of aphids, whiteflies, thrips and other pests. All tested botanical insecticides showed high biological efficacy and can be used to control the mealy plum aphid. Keywords: mealy plum aphid, biological control, botanical insecticides, Limocid, Basictec, Abanto, Hyalopterus pruni

Status of Invasive Species of Thrips, Thrips Parvispinus (Karny) Infesting Chilli and Investigation Studies on IPDM Package in Dharmapuri Districts, Tamil Nadu, India

Roving survey results revealed that mean population of thrips, mite population and tospovirus incidence was recorded to be 1.63, 0.68 & 2.05 and 1.88, 0.74 & 1.57 in Pennagaram and Palacode blocks. In the field experiments, mean population in the module I IPDM module was recorded low thrips population (1.05 nos./leaf and 0.64 nos/Sq.m2 leaves) followed by module II IPDM (1.11 Nos./leaf and 0.71nos/Sq.m2 leaves). A virus incidence of 1.0 to 2.0 % was recorded in treatment 2 module II and treatment 3 Farmers practices 2.2 to 9.5 % was observed. The per cent reduction over control of thrips and mite population is highest in T1 followed by T2 and farmer practice (81.70, 80.66 and 56.48 % & 79.61,77.38 and 33.12 %). The percent reduction over control of tospovirus by thrips is highest in T1 IPDM module followed IPDM II than farmer practice (100, 88.88 and 54.40%). The yield of green chilli and BC ratio were found to be high in IPDM module (22.96 t/ha and 3.02) followed by module II IPDM (19.14 t/ha and 2.78) followed by farmer’s practice (13.88 t/ha and 1.49).

Optimized nanopesticide delivery of thiamethoxam to cowpeas (Vigna unguiculata) controls thrips (Megalurothrips usitatus) and reduces toxicity to non-target worker bees (Apis mellifera)

Thrips [Megalurothrips usitatus (Bagnall)] (Thysanoptera: Thripidae) is a pest that poses a serious challenge to global crop production and food supply, especially to the cowpea industry. Nano-delivery systems have broad application prospects in the prevention and control of pests in agriculture. Herein, three types of amino acid (AA) modified polysuccinimide nano-delivery carriers (PSI-GABA, PSI-ASP and PSI-GLU) were constructed with a diameter of approximately 150 nm to load thiamethoxam (THX), which enhanced THX effective distribution and use with cowpea plants. Significantly, the PSI-GLU nanocarrier effectively delivered THX to cowpea plant tissues following 6 h of soil application. Compared with commercial THX suspension (SC), the THX content in the leaves of cowpea plants was increased by 2.3 times. Confocal laser scanning microscopy revealed that the FITC-labeled PSI-GLU nanocarrier reached the leaves through the vascular system after being absorbed by the roots of cowpea plants. The PSI-GLU nanocarrier decreased the LC50 of THX from 11.45 to 7.79 mg/L and significantly enhanced the insecticidal effect. The PSI-GLU nanocarrier also improved the safety of THX to worker bees at 48 h, and moreover showed a growth-promoting effect on cowpea seedlings. These results demonstrated that the PSI-GLU nano-delivery carrier has promising uses on improving the effective utilization of THX for the sustainable control of thrips and reducing the risk to non-target pollutions.

Synergistic Strategies for the Management of Thrips, Scirtothrips dorsalis in Pomegranate Ecosystem

Thrips management in pomegranate cultivation is critical due to the significant damage these pests can inflict on fruit yield and quality. The study was carried out in farmers field at Managuli, Vijayapura, College of Agriculture, Vijayapura, Karnataka during 2020-2021. The integrated management of thrips, Scirtothrips dorsalis in pomegranate revealed that the in-situ vermiculture technique along with chemicals (86.93 per cent) and botanicals (59.40 %) found to be more effective in controlling thrips than in-situ vermiculture technique alone (39.22 %). It also revealed that in-situ vermiculture technique influencing only 2-5 % pest reduction along with chemical insecticides. Whereas, in-situ vermiculture technique along with botanical influencing 15-20 % pest reduction and it mainly due to compatibility and positive effect of botanicals on earthworms than chemicals. However, all the treatments recorded higher yield and found significantly superior over untreated control (5.34 t/ha). By integrating these methods, pomegranate growers can achieve effective thrips control, leading to healthier crops, improved yields while promoting sustainable agricultural practices and minimizing environmental impact.

Spraying dsRNA with chitosan formulation improves control of the western flower thrips, Frankliniella occidentalis, in a greenhouse.

The western flower thrips, Frankliniella occidentalis, is a serious pest causing both direct feeding damage and indirect harm by transmitting the tomato spotted wilt virus. A spraying double-stranded RNA (dsRNA) targeted at the vacuolar-type ATPase (vATPase) gene was developed and demonstrated high insecticidal activity in the laboratory but less effective in field applications. To improve control efficacy under field conditions, three strategies were explored in this study. First, to identify a more efficient RNA interference (RNAi) target, dsRNA specific to the Snf7 gene was tested alongside dsRNA targeting vATPase, and both were found to be similarly effective in controlling the thrips. Second, to elucidate the factors contributing to dsRNA resistance, dsRNA-degrading enzymes were annotated and their physiological roles in diminishing RNAi efficacy were investigated. Third, to suppress the dsRNA degradation from the dsRNase activities and protect it in field conditions, the dsRNA was encapsulated with chitosan. This formulation enhanced the dsRNA's resistance to environmental stressors such as ultraviolet light and the digestive enzymes in the thrips' gut. Additionally, the chitosan formulation specifically increased the RNAi efficacy, likely by facilitating more efficient entry into the target cells, thus bolstering the insecticidal activity of the dsRNA. The formulated dsRNA was applied on F. occidentalis infesting the hot peppers in a greenhouse at a concentration of 500 ppm, demonstrating an 82.4% control efficacy compared with 59.2% control efficacy observed with the application of naked dsRNA. This study further demonstrated an enhancement in the spectrum of control by combining dsRNAs specific to three distinct thrips species, while the mixture showed no adverse effects on non-target insects, such as the lepidopteran Spodoptera exigua. Collectively, these findings reveal that the chitosan formulation of dsRNA not only improves control efficacy under field conditions but also broadens the control spectrum against three different thrips pests.

Enhancing hoverfly activity with flowering buckwheat for effective control of onion thrips (Thrips tabaci) in onion–barley intercropped Fields

Enhancing hoverfly activity with flowering buckwheat for effective control of onion thrips (Thrips tabaci) in onion–barley intercropped Fields

Species of Phytoseiidae (Acari: Mesostigmata) predators of thrips and whiteflies: a review

The biological control of thrips and whiteflies, major pests of crops in greenhouses, is mainly based on the use of hymenopteran parasitoids and many predatory species. Several species of the family Phytoseiidae are natural enemies of these pests. Although several phytoseiid species have been commercially available in the last two decades, more and more research on their efficiency has been accumulated. Data on many additional species as potential predators has been published but research is still limited. This manuscript aims to present the results of relatively recent research about each phytoseiid species studied/commercialized to control whiteflies and thrips. The phytoseiid mite species are divided into three groups: predators that prey on whiteflies and thrips with a preference for phytophagous mites, those commercially produced for managing whiteflies and thrips, and those needing further research to clarify their potential. Available information about the efficacy and limitations of each species is provided and future perspectives for their use are proposed.

Comparison of toxicity of some synthetic insecticides against thrips (Thrips tabaci) on cotton crop under different irrigation regimes

Cotton is the main cash crop and back bone of agriculture. However, its yield is decreasing due to insect pests attack. Among them, sucking insect pests are serious problem in cotton and various agricultural crops. Hence, present research work was executed to assess the toxicity of some synthetic insecticides against Thrips tabaci in cotton crop. The research trial was executed with varied planting geometry under different irrigation regimes. Sowing of the cotton crop was done with plant to plant distance of 30 and 60 cm while row to row distance was 4 ft. apart. The plants were irrigated under single lateral and double lateral arrangements of drip irrigation while control plot was irrigated through conventional surface irrigation method. Results of relative incidence of thrips population on different irrigation plots showed that highest thrips population (19.43/plant) was noted in case of flood irrigated plot having plant to plant distance of 30 cm followed by in double lateral drip irrigation plot (15/plant) and single lateral plot (13.10 thrips/plant). Comparatively lower mean thrips population values; 16.30, 12.40 and 10.56 thrips/plant, respectively were recorded in experimental plot under 60 cm plant to plant distance. Toxicity bioassays revealed that highest reduction (75.27%) was recorded in spinetoram while lowest thrips population reduction (28.18%) was recorded in case of spinosad. It can be concluded that spinetoram can be effective tool for efficient control of thrips leading to augmentation in cotton crop yield.

The use of ecologically safe means in the protection against sucking phytophages in the ampelocenoses of the Northern Black Sea region

Goal. To provide data on insecticides for protection of grapes from thrips and Japanese grape cicada and their influence on the number of entomophages, which is an important element for the organization of effective and environmentally friendly technology of grape growing.
 Methods. Combination of quantitative and qualitative methods in plant protection — entomology and biomethod. The use of generally accepted methods of analysis (hypothesis, experiment, induction and synthesis) provides sufficient information on the control of grape thrips and Japanese grape cicada under the conditions of using environmentally friendly means of protection, which is one of the main elements of modern technologies for optimizing agroecosystems and obtaining environmentally friendly products. The phytosanitary method of route surveys involves the identification of entomophages and the establishment of dominant species and prevalence of grape thrips and Japanese grape cicada among them. The field method ensures the study of the effectiveness of the elements of the integrated grape crop protection system. The laboratory method involved the identification of species diversity of beneficial fauna. The statistical method was used to calculate the data obtained, determine their accuracy and reliability.
 Results. The database was updated with environmentally safe products, and regulations for their use were established, which are focused not so much on pest control as on the overall optimization of the phytosanitary condition of plantations, obtaining environmentally friendly products and preserving beneficial fauna. Under natural conditions, without pesticide pressure, the number of predators in a multicomponent entomocomplex is many times higher than in traditional agrocenoses.
 Conclusions. The composition of preparations with a given direction of minimizing damage to beneficial fauna and, accordingly, the environment was formed. The results obtained and the conclusions formulated on their basis are of practical importance in terms of the prospects for the production of environmentally friendly products by applying environmentally friendly and effective methods of controlling the number of sucking pests and preserving the natural agrobiocenosis.

Effects of Various Nectar and Pollen Plants on the Survival, Reproduction, and Predation of Neoseiulus bicaudus.

Neoseiulus bicaudus is a predatory mite species that could potentially be used for the biological control of spider mites and thrips. Floral resources can provide excellent habitats and abundant nutrients for natural enemies. The objective of this experiment was to evaluate the effects of eight floral resources on the longevity, fecundity, and predation ability of N. bicaudus. Among the considered plants, Cnidium monnieri led to the highest longevity (24 days) and fecundity (13.8 eggs) of N. bicaudus, while Tagetes erecta resulted in the lowest longevity (7 days) and fecundity (0.1 eggs) observed in the predatory mites. By comparing the effects of three nectar and pollen plants on the predation of predatory mites, it was observed that N. bicaudus still exhibited a type II functional response to Tetranychus turkestani. In the presence of pollen, the predation efficacy (a/Th) of N. bicaudus exhibited a lower value, compared to that in the absence of pollen (Control: a/Th = 24.00). When pollen was supplied, the maximum consumption (1/Th) of predatory mites was higher than in its absence (Control: 1/Th = 9.90 d-1), with the highest value obtained in the presence of B. officinalis pollen (B. officinalis: 1/Th = 17.86 d-1). The influence coefficient of predation of N. bicaudus on T. turkestani in the presence of pollen was compared in the presence of three nectar and pollen plants: Cnidium monnieri, Centaurea cyanus, and Borago officinalis. At low prey densities, the influence coefficient of C. cyanus exceeded that of B. officinalis, and the overall influence coefficient values were negative (i.e., the presence of pollen reduced predatory mite feeding on T. turkestani). They exhibited similar values at high prey densities, and all of the influence coefficient values were close to 0 (i.e., the presence of pollen had no effect on predatory mite feeding on T. turkestani). The findings revealed that diverse plant species exert differential impacts on N. bicaudus, with some influencing its lifespan and others affecting its reproductive capabilities. Furthermore, the presence of nectar and pollen plants had a significant impact on predatory mite feeding on T. turkestani at low prey densities; however, this effect diminished as the prey density increased. Therefore, we recommend planting C. monnieri, C. cyanus, and B. officinalis in the field to ensure an ample population of predatory mites. The obtained results hold significant implications for the utilization of nectar and pollen plants in eco-friendly pest management strategies within agricultural contexts.

Adhesive droplets made from plant-derived oils for control of western flower thrips

AbstractArthropod pests cause significant problems in agricultural crops all around the world. As chemical pesticide use becomes less desired, there is a need for alternative methods of pest control. Inspired by the natural adhesiveness of arthropod trapping plants, we examined the effectiveness of adhesive droplets made from oxidised and cross-linked plant-derived oils for control of western flower thrips. Two filter paper droplet adhesiveness assays and three detached chrysanthemum leaf assays were carried out to test efficacy against thrips. Suspensions containing adhesive droplets and other constituents were applied to filter papers and leaves via spraying or dipping. On filter papers, droplets made from oxidised rice germ oil (RGO) of different sizes caught 40–93% of thrips. Droplets made of a mixture of sunflower, olive, and linseed oil (MIX) caught up to 94% of thrips. Likewise, adhesive droplet-treated filter papers showed higher thrips mortality than untreated or control solution-treated filter papers. On chrysanthemum leaves, thrips were caught by both RGO (up to 40%) and MIX droplets (up to 20%) and thrips damage and reproduction were reduced. On MIX-treated leaves, thrips mortality was also increased. Within treatments, droplets of different size classes occurred and larger droplets were more effective at catching thrips in general. Droplets were also robust to rinsing with water, which is of importance for their application in horticulture. In conclusion, adhesive droplets made from edible plant oils show potential for use in control of western flower thrips.

Evaluation of fumigant toxicity of cyclohexanone to 5 species of insect pests.

Cyclohexanone is a major precursor for nylon production and is also used as a pesticide solvent. In this study, cyclohexanone was evaluated as a fumigant against rice weevil adults, confused flour beetle adults, western flower thrips larvae and adults, spotted wing drosophila adults, and subterranean termite workers. Cyclohexanone fumigation was effective against all 5 insects, and there were considerable variations in susceptibility to cyclohexanone fumigation among the 5 species. At 20 °C, complete control of spotted wing drosophila adults was achieved in 1-h fumigation with 25 μl/l of cyclohexanone and complete control of eastern subterranean termite workers was achieved in 3-h fumigations with 50 μl/l dose of cyclohexanone. Stored-product insects confused flour beetle, and rice weevil adults were more tolerant to cyclohexanone fumigation. Fumigations of 24 h with 75 μl/l dose of cyclohexanone caused 100% mortality of rice weevil adults and 98% mortality of confused flower beetle adults. Even at a 100 μl/l dose, the 24-h fumigations did not achieve 100% mortality of confused flour beetle adults. At 5 °C, complete control of western flower thrips was achieved in 3- and 6-h fumigations with 100 and 50 μl/l doses of cyclohexanone, respectively. Cyclohexanone vapor concentrations were measured using cyclohexanone detector tubes. Vapor concentrations were far below the expected saturation concentration indicating that most cyclohexanone did not exist as vapor in fumigation chambers. The results of effective control of all 5 insect species suggest that cyclohexanone has the potential to be used as a fumigant for postharvest pest control.

Why does identification matter? Thrips species (Thysanoptera: Thripidae) found in soybean in southern Brazil show great geographical and interspecific variation in susceptibility to insecticides

Thrips have historically been considered secondary soybean pests in Brazil and neighboring countries. However, since the 2010s they have gained importance in soybean in central and northern Brazil. From 2017 onwards, high infestations of thrips have also been detected in soybean in southern Brazil. Here, we collected and identified thrips species from soybean fields in southern Brazil throughout the 2022/2023 season and conducted laboratory bioassays to assess their susceptibility to selected insecticides. Thrips were exposed to the field concentrations of selected insecticides in leaf-dip bioassays using soybean leaves. Our results indicated that Frankliniella schultzei (Trybom, 1910) and Caliothrips phaseoli (Hood, 1912) are the major thrips species found in soybean in southern Brazil. These species exhibited high mortality and relatively low geographic and interspecific variation in susceptibility to the field concentrations of spinetoram, methomyl, spinetoram + methoxyfenozide and profenofos + cypermethrin. In general, most populations of C. phaseoli were more susceptible to acephate, chlorfenapyr and abamectin than F. schultzei, whereas bifenthrin + carbosulfan showed high lethality against most populations of F. schultzei, however, both species had wide geographic variation in susceptibility to these chemistries. In contrast, populations of both species have low mortality when exposed to the field concentrations of imidacloprid, lambda-cyhalothrin and lambda-cyhalothrin + sulfoxaflor. In summary, our study documents significant variations in the susceptibility of F. schultzei and C. phaseoli to selected insecticides, both among species and among geographical areas across southern Brazil. These results highlight the importance of species identification for the effective control of thrips in soybean in Brazil and other South American countries.

Functional response estimations of Chrysoperla carnea to different densities of Aphis craccivora and Gynaikothrips ficorum nymphs.

The functional responses of Chrysoperla carnea larvae were evaluated at different seven densities of the 3rd instar nymphs of Aphis craccivora and Gynaikothrips ficorum in order to find out the relationship between predator densities and its prey by the, and also to find out their capability for biological control of aphids and thrips. Results revealed that all tested larval instars of Ch. carnea exhibited a type II response in relation to the prey. Moreover, the coefficients of attack rate (a) and handling time (Th) was differed among various growing instars of predator and for the prey species. The 3rd instar larvae of Ch. carnea manifested the highest attacking rate (1.23 and 1.22) on the 3rd instar nymphs of A. craccivora and G. ficorum, respectively. In addition it exhibited the highest maximum predation (Na max) (50.00 and 52.63) on A. craccivora and G. ficorum nymphs, respectively as compared with the other treatments. Accordingly, Ch. carnea could be considered as a promising bio-control agent for A. craccivora and G. ficorum management.

Control of flower thrips on rabbiteye blueberry, 2024

Control of flower thrips on rabbiteye blueberry, 2024

Soil systemic insecticides for control of western flower thrips on romaine lettuce, 2022

Soil systemic insecticides for control of western flower thrips on romaine lettuce, 2022

Evaluation of Torac in full-season insecticide programs for thrips control in onion in Wisconsin, 2023

Evaluation of Torac in full-season insecticide programs for thrips control in onion in Wisconsin, 2023

Evaluation of foliar insecticide treatments for thrips control in onion, 2022

Evaluation of foliar insecticide treatments for thrips control in onion, 2022

Go west: Population genomics reveals unexpected population fluctuations and little gene flow in Western hemisphere populations of the predatory lady beetle, Hippodamia convergens.

Hippodamia convergens-the convergent lady beetle, has been used extensively in augmentative biological control of aphids, thrips, and whiteflies across its native range in North America, and was introduced into South America in the 1950s. Overwintering H. convergens populations from its native western range in the United States are commercially collected and released across its current range in the eastern USA, with little knowledge of the effectiveness of its augmentative biological control. Here we use a novel ddRADseq-based SNP/haplotype discovery approach to estimate its range-wide population diversity, differentiation, and recent evolutionary history. Our results indicate (1) significant population differentiation among eastern USA, western USA, and South American populations of H. convergens, with (2) little to no detectable recent admixture between them, despite repeated population augmentation, and (3) continued recent population size expansion across its range. These results contradict previous findings using microsatellite markers. In light of these new findings, the implications for the effectiveness of augmentative biological control using H. convergens are discussed. Additionally, because quantifying the non-target effects of augmentative biological control is a difficult problem in migratory beetles, our results could serve as a cornerstone in improving and predicting the efficacy of future releases of H. convergens across its range.