Thrips Infestation Research Articles

Field Evaluation of Integrated Pest Management Strategies against Chilli Black Thrips Thrips parvispinus (Karny), in the Srikakulam District

Chilli (Capsicum annum L) is an important spice crop grown extensively in India for both domestic and export markets. Invasive black thrips Thrips parvispinus has been causing destructive damage to chilli crop in India leading to indiscriminate use of insecticidal sprays. On-farm trials were conducted during Kharif and Rabi 2022-23 & 2023-24 to evaluate Integrated Pest Management practices against black thrips with emphasis on minimal pesticidal sprays with different mode of actions so that pests may not develop resistance which will reduce the residues on the produce in the farmer’s fields of Srikakulam district of Andhra Pradesh. IPM adopted fields i.e. seed treatment, marigold as trap crop, erection of blue sticky traps, Beauveria bassiana spray and Neem oil and Fipronil 5 SC spray at 30 DAT; Imidacloprid+Fipronil 40%WG spray at 50 DAT; have shown 40 to 85 per cent reduction in black thrips infestation over farmers practice during all the seasons of both the years. This resulted in a higher average mean yield of 57 q/ha, average net returns of Rs. 4,96,000 per hectare with cost benefit ratio of 3.29 in IPM fields over farmer’s practice depicting that the adoption of IPM practices helped in reducing the pest incidence and increase in yield, net returns.

Seasonal Incidence of Onion Thrips, Thrips tabaci Lindeman in Gird Region of Madhya Pradesh, India

An investigation was undertaken to study the seasonal incidence of onion thrips, Thrips tabaci Lindeman, on onion in the Grid region of Madhya Pradesh, India. The experiment revealed that the thrips infestations in plants occurred during 52 Standard Metrological Week (SMW) in 2022–23 and 2023–24, with an average of 6.28 and 5.80 thrips per plant, respectively. The maximum incidence was 41.70 and 41.98 thrips per plant, respectively, during the 9 SMW in both consecutive years. The number of thrips was significantly positively correlated with minimum and maximum temperature during both the consecutive years of study. However, evening relative humidity was negatively correlated with thrips population during 2022–23 and 2023-24, but the morning relative humidity showed negative correlation only during 2022-23.

Orthotospovirus iridimaculaflavi (iris yellow spot virus): An emerging threat to onion cultivation and its transmission by Thrips tabaci in India

The yellow spot disease caused by the virus species Orthotospovirus iridimaculaflavi (Iris yellow spot virus-IYSV), belonging to the genus Orthotospovirus, the family Tospoviridae, order Bunyavirales and transmitted by Thrips tabaci Lindeman. At present, emerging as a major threat in onion (Allium cepa) in Tamil Nadu, India. The yellow spot disease incidence was found to be 53–73 % in six districts out of eight major onion-growing districts surveyed in Tamil Nadu during 2021–2023. Among the onion cultivars surveyed, the cultivar CO 5 was the most susceptible to IYSV. The population of thrips was nearly 5–9/plant during vegetative and flowering stages. The thrips infestation was 34–60 %. The tospovirus involved was confirmed as IYSV through DAS-ELISA, followed by molecular confirmation through RT-PCR using the nucleocapsid (N) gene. The predominant thrips species present in onion crops throughout the growing seasons was confirmed as Thrips tabaci based on the nucleotide sequence of the MtCOI gene. The mechanical inoculation of IYSV in different hosts viz., Vigna unguiculata, Gomphrena globosa, Chenopodium amaranticolor, Chenopodium quinoa and Nicotiana benthamiana resulted in chlorotic and necrotic lesion symptoms. The electron microscopic studies with partially purified sap from onion lesions revealed the presence of spherical to pleomorphic particles measuring 100–230 nm diameter. The transmission of IYSV was successful with viruliferous adult Thrips tabaci in cowpea (Cv. CO7), which matured from 1st instar larva fed on infected cowpea leaves (24 h AAP). Small brown necrotic symptoms were produced on inoculated plants after an interval of four weeks. The settling preference of non-viruliferous and viruliferous T. tabaci towards healthy and infected onion leaves resulted in the increased preference of non-viruliferous thrips towards infected (onion-61.33 % and viruliferous thrips towards healthy onion leaves (75.33 %). The study isolates shared 99–100 % identity at a nucleotide and amino acid level with Indian isolates of IYSV in the N gene. The multiple alignment of the amino acid sequence of the N gene of IYSV isolates collected from different locations and IYSV isolates from the database revealed amino acid substitution in the isolate ITPR4. All the IYSV isolates from India exhibited characteristic amino acid substitution of serine at the 6th position in the place of threonine in the isolates from Australia, Japan and USA. The phylogenetic analysis revealed the monophyletic origin of the IYSV isolates in India.

Field Evaluation of Sweet Potato Genotypes for Resistance to <i>Cylas formicarius</i>

Sweet potato weevil Cylas formicarius is a major insect pest in Siang valley of Arunachal Pradesh which inflicts damage on the leaves, vines, and tubers as part of their normal feeding and survival habit. The study was conducted to evaluate 29 local genotypes of Northeast India, along with two commercial cultivars, Sree Bhadra and ST-14, for their relative susceptibility to pest. Sweet potato weevil and grasshopper incidence on the vines were lowest in CHFSP-10, while thrips infestations was lowest in CHFSP-07. In terms of tuber incidence, the genotypes CHFSP-10, CHFSP-14and CHFSP-15 performed better against C. formicarius. The substantially decreased sensitivity of CHFSP-10, CHFSP-14 and CHFSP-15 to sweet potato weevil indicates the feasibility of using them in varietal development to improve breeding programmes.

First Report of Invasive Thrips, Thrips parvispinus (Karny) (Thysanoptera: Thripidae) in chilli from Alipurduar District of West Bengal, India

Chilli (Capsicum annum L.) is one of the important commercial crops grown in almost all the states of India. However, biotic ravages caused by insect pests limit the productivity and quality of this crop. Recently thrips infestation was recorded in chilli crop in Guabar Nagar village under Alipurduar district of West Bengal. Survey was conducted and thrips specimens were collected from flowers of infested plants. The thrips was identified as Thrips parvispinus on the basis of molecular characterization. The submission of the said sequence to National Center for Biotechnology Information (NCBI) database resulted in generation of GenBank accession number PP338266. Upon confirmation of the pest as the invasive T. parvispinus, extended surveys were conducted in the neighbouring villages and this invasive thrips was also found in the farmers’ fields of Harinathpur, Baganbari, Dhulagaon and Nabanagar villages of the Alipurduar district of West Bengal.

Resistance to Frankliniella occidentalis during Different Plant Life Stages and under Different Environmental Conditions in the Ornamental Gladiolus.

The defense mechanisms of plants evolve as they develop. Previous research has identified chemical defenses against Western flower thrips (WFT) in Gladiolus (Gladiolus hybridus L.). Consequently, our study aimed to explore the consistency of these defense variations against WFT across the various developmental stages of Gladiolus grown under different conditions. Thrips bioassays were conducted on whole plants at three developmental stages, using the Charming Beauty and Robinetta varieties as examples of susceptible and resistant varieties, respectively. Metabolomic profiles of the leaves, buds and flowers before thrips infestation were analyzed. The thrips damage in Charming Beauty was more than 500-fold higher than the damage in Robinetta at all plant development stages. Relative concentrations of triterpenoid saponins and amino acids that were associated with resistance were higher in Robinetta at all plant stages. In Charming Beauty, the leaves exhibited greater damage compared to buds and flowers. The relative concentrations of alanine, valine and threonine were higher in buds and flowers than in leaves. The Metabolomic profiles of the leaves did not change significantly during plant development. In addition, we cultivated plants under different environmental conditions, ensuring consistency in the performance of the two varieties across different growing conditions. In conclusion, the chemical thrips resistance markers, based on the analysis of vegetative plants grown in climate rooms, were consistent over the plant's lifetime and for plants grown under field conditions.

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.

Copper and Silver Nanoparticle Seed Priming and Foliar Spray Modulate Plant Growth and Thrips Infestation in Capsicum spp.

Nanoparticles (NPs) have the potential to improve plant health and secondary metabolite production. In the present study, three different NPs, i.e., Ag, Cu, and Cu-Ag NPs were produced in the range from 25 to 86 nm, with zeta potentials ranging from -28.8 to -38.5 mV. The synthesized NPs were used for seed priming and foliar spray on three varieties of Capsicum annuum. L, i.e., Arka Sweta (AS), Arka Meghana (AM), and Arka Harita (AH) plants grown under greenhouse conditions. Seed priming at various concentrations of NPs (1, 10, 20 ppm) enhanced the seed germination (96%), seedling vigor index (2494-3112.66), seedling length (6-49%), and biomass (46%) of 45 days old Arka Meghana seedlings. Additionally, all plant tissues accumulated significantly higher amounts of chlorophyll (51-142%), carotenoids (23-94.2%), total phenolic content (73%), and total flavonoid content (57%), compared with the control (p ≤ 0.05). The foliar spray of NPs (20-100 ppm) has a protective effect on the chili plants against thrips infestation (30-76%). The foliar spray enhanced chlorophyll (15-62%), carotenoids (15-50%), total phenolic content (20-62%), total flavonoid content (64-99%), reducing sugars (15-97%), total antioxidant activity (15-142%), ferric reducing antioxidant power assay (15-109%), DPPH (129-54 mg mL-1), and capsaicinoids (capsaicin and dihydrocapsaicin) (82-128%). This study illustrates that Ag, Cu, and Cu-Ag NPs suppress thrips infestation and proliferation with enhanced plant growth and biochemical activity, which is inversely proportional to the NP size. Chemical NPs play a crucial role in the economic significance of chili plants, offering a promising avenue for developing pesticides to effectively combat thrips infestation. This advancement holds great potential in enhancing the overall agronomic productivity of the chili crops.

Transient composition of the thrips species (Thysanoptera: Thripidae) infesting mulberry in southern India: first report of two, including the dominating invasive pest Thrips parvispinus

Abstract Alerted by the steady upsurge of thrips infestation that led to drastic leaf-yield losses in mulberry, we investigated the composition of thrips species damaging the crop in the south Indian states of Andhra Pradesh, Karnataka, and Tamil Nadu from 2017 to 2023. The 5 species recorded included 3 previously recognized mulberry pests—Bathrips melanicornis, Pseudodendrothrips darci, and Scirtothrips dorsalis—and 2 newly encountered pests, namely Thrips palmi and Thrips parvispinus. At Handenahalli village in Anekal taluk of Bengaluru Urban district in Karnataka, where multiple thrips species simultaneously infested mulberry, the typical downward curling of leaves was ascribed to T. parvispinus. This was in contrast to the upward curling caused by the sole infestation of P. darci, the most common species infesting mulberry across the 3 states. Diagnostic characters of all the reported species are presented here along with the identification keys and photomicrographs. Thrips parvispinus as a new pest of mulberry warrants special attention given the economic loss caused by this highly polyphagous invasive species in chili in southern India during the latter half of 2021. Its presence in the transient composition of mulberry-infesting thrips species signals the possibility of it becoming a regular pest in the future with serious repercussions for the moriculture and sericulture sectors.

Efficacy of Bio-Rational Insecticides in Controlling Thrips in Summer Country Bean

Aims: To study the efficacy of biorational insecticides in controlling thrips in summer country bean.
 Study design: The study used a single component Randomized Complete Block Design (RCBD) with three replications.
 Place and Duration of Study: The experiment was conducted in the central farm of Sher-e-Bangla Agricultural University, Dhaka, Bangladesh from March to May 2021.
 Methodology: The experiment consisted of seven treatments and was laid in a single factor Randomized Complete Block Design (RCBD) with three replications. The experiment consists of the following management practices: T1=Spraying Neem oil @ 6 ml/L of water at 7 days interval, T2=Spraying Neem leaf extract @ 200 mg/L of water at 7 days interval, T3= Mehgoni leaf extract @ 200 mg/L of water at 7 days interval, T4=Tobacco leaf powder @ 30 mg/L of water at 7 days interval, T5= Spraying Spinosad @ 0.4 ml/L of water at 7 days interval, T6=Spraying Biotrin @1.4 ml/L of water at 7 days interval and T7= Untreated control.
 Results: Among the seven (7) treatments the lowest number of thrips (2.50 plant-1) was observed in T5 (Spraying Spinosad @ 0.4 ml/L of water at 7 days interval), while highest number of thrips (16.67 plant-1) was observed in T7 (Untreated control). The highest percentage of thrips reduction over control (85.50%) was observed in T5 (Spraying Spinosad @ 0.4 ml/L of water at 7 days interval) treatment. The present study revealed that the lowest number of thrips as insect pest and increased plant, leaf, inflorescence and pod infestation, different yield contributing characters and yield of country bean might be obtained by using the treatment T5 (Spraying Spinosad @ 0.4 ml/L of water at 7 days interval) besides T6 (Spraying Biotrin @ 1.4 ml/L of water at 7 days interval) performed as second best treatment whereas, T7 (Control) and T3 (Mehgoni leaf extract @ 200 mg/L of water at 7 days interval) may protect the country bean at lowest rate in summer.
 Conclusion: It can be concluded that, spraying of Spinosad @ 0.4ml/L of water at 7 days interval as a bio-rational management practice for thrips population control for country bean variety BARI Sheem-4 in summer reduced the infestation of thrips at the most satisfactory level.

Chitosan nanoparticles modulate plant growth, and yield, as well as thrips infestation in Capsicum spp.

The objective of this study was to investigate the physiological and biochemical effects of Chitosan nanoparticles on Capsicum annuum plants. The particle size, polydispersity index, composition, and structure of the synthesized chitosan-based nanoparticles (Chitosan (CS), Chitosan-Silver (CSAg), and Chitosan-Copper (CSCu) NPs) were determined by analyzing the zeta potential, FTIR, TEM, and XRD. The seedlings showed improved physiological and biochemical characteristics when 1, 10, and 20 ppm concentrations of nanoparticles (CS, CSAg, and CSCu) were used for 24-h seed priming. The application of nanoparticles in different concentrations (0, 20, 40, 60, 80, and 100 ppm) on the leaves of Capsicum spp. plants resulted in improved physiological traits and protection against thrips by 70–85 %. Furthermore, it enhanced the content of chlorophyll (20–75 %), carotenoids (20–30 %), total phenolics (20–45 %), total flavonoids (40–125 %), reducing sugars (15–40 %), total antioxidant activity (10–82 %), FRAP (10–100 %), DPPH (76-83 mg mL−1) activity, and total capsaicinoids (125–142 %). Therefore, the use of chitosan-based nanoparticles could be considered an environmentally friendly approach to enhance secondary metabolite production, disease resistance, and growth in Capsicum spp. plants for sustainable production.

Assessment of Trap Crops for Management of Thrips, T. tabaci in Tomato

The prospect of four trap crops viz., marigold, okra, sunflower and brinjal were evaluated for their efficiency against thrips, T. tabaci at SASRD, Medziphema, Nagaland University. The study was conducted in Split Plot Design with four treatments having three replications. Tomato was grown on two different planting geometries i.e. 90 x 70 cm (P1) and 60 x 60 cm (P2) and the treatments used as trap crops were indicated as marigold (T1), okra (T2), brinjal (T3) and sunflower (T4), while confining a ratio of main crop to trap crop at 4: 1.The trap crops were transplanted first following the pattern of sequential trap- cropping. Thrips infestations were recorded from the early vegetative stage of tomato and decline in population as the crop matured. All trap crops in the present study showed good performance in the management of T. tabaci. The planting geometry, P2 with okra as a trap crop was observed to be reasonably effective in curbing thrips population in the study period.

Ecological Interactions among Thrips, Soybean Plants, and Soybean Vein Necrosis Virus in Pennsylvania, USA.

Analysis of ecological and evolutionary aspects leading to durability of resistance in soybean cultivars against species Soybean vein necrosis orthotospovirus (SVNV) (Bunyavirales: Tospoviridae) is important for the establishment of integrated pest management (IPM) across the United States, which is a leading exporter of soybeans in the world. SVNV is a seed- and thrips- (vector)-borne plant virus known from the USA and Canada to Egypt. We monitored the resistance of soybean cultivars against SVNV, surveyed thrips species on various crops including soybeans in Pennsylvania, and studied thrips overwintering hibernation behavior under field conditions. Field and lab experiments determined disease incidence and vector abundance in soybean genotypes. The impact of the virus, vector, and their combination on soybean physiology was also evaluated. Seed protein, fiber, oil, and carbohydrate content were analyzed using near infra-red spectroscopy. We found that the variety Channel3917R2x had higher numbers of thrips; hence, it was categorized as preferred, while results showed that no variety was immune to SVNV. We found that thrips infestation alone or in combination with SVNV infection negatively impacted soybean growth and physiological processes.

Field Evaluation of Biorationals and Chemical Insecticides against Thrips parvispinus (Karny) (Thysanoptera: Thripidae), in Chrysanthemum

Field study was conducted to evaluate the efficacy of biorationals and chemical insecticides against black thrips, Thrips parvispinus (Karny) on chrysanthemum. Thrips population ranged from 15.33 to 13.89/flower before spraying. The efficacy of seven biorationals and seven chemical insecticides were evaluated against black thrips under field conditions. The application of pongamia soap @5g/lit and Spinosad 45% SC @ 0.2 ml/lit reduced the thrips incidence significantly among the biorational and chemical insecticides respectively. The mean per reduction of thrips incidence in pongamia soap @ 5 gm/lit application was 74.90%. This was followed by neem soap @ 5g/lit (72.25%), azadirachtin @10000ppm (71.10%), Beauveria bassiana (66.76%), Isaria fumosorosea (64.93%), Lecanicillium lecanii (63.72%), and Metarhizium anisopilae (62.46%). Among the chemical insecticides Spinosad 45%SC @ 0.2 ml/lt. stood first in the order of efficacy with 80.2% reduction in thrips population. The order of efficacy of chemical insecticides against black thrips in chrysanthemum are spinetoram 11.7%SC (76.245%) > cyantraniliprole 10%OD (73.92%) > fipronil 5% SC (72.24%) > thiamethoxam 25% WG (70.79%) > dinotefuran 20% WG (69.80%) > tolfenpyrad 15% EC (68.02%). The effective biorational and chemical insecticide can be included as a component in the Integrated pest management of thrips complex in chrysanthemum. The rotation of effective compounds will reduce the resistance development against insecticides in thrips associated with chrysanthemum and also reduces the thrips infestation.

Identification of Superior Genotypes for Yield and Quality in Multiplier Onion

Background: Multiplier onion is one of the most important crops of Tamil Nadu. It is having lot of health benefits like anti-inflammatory, anti cholesterol, anticancer and antioxidant properties, lowering the toxigenicity of oils. It also shows chemo preventive effects and lowers down the risk of effect on gastric cancer. Considering the importance of multiplier onion an attempt was made to evaluate the multiplier onion genotypes to identify the best yielding genotype.
 Methods: Seven genotypes of multiplier onion (Allium cepa var aggregatum) were evaluated under Northern transitional zone of Karnataka at University of Agricultural Sciences, Dharwad both during Kharif and Rabi for yield and quality parameters.
 Results: The outcome of the experiment revealed that over the seasons, the genotype MP16-24 was registered highest total yield (167.86 q/ha), marketable yield (160.41q/ha), TSS (15.41), average bulb weight (4.64g)and less number of bolters, low infestation of thrips (7.83) and purple blotch (7.66). Therefore, the genotype MP 16-24 can be commercially grown under Dharwad conditions during both Kharif and Rabi because of its favorable characters.

AKURASI PENILAIAN SERANGAN Thrips sp. PADA DAUN CABAI BERDASARKAN PENGAMATAN VISUAL DAN PENGOLAHAN CITRA

Visual observation is a method of assessing the intensity of thrips infestation that assessors favor because it is relatively easy to apply. However, on the other hand, it has many limitations. Therefore, a more accurate alternative method, such as digital image processing, is needed. This study aims to evaluate the accuracy of visual observation and digital image processing used to assess the thrips attack on cayenne pepper leaves. This study was designed following a Randomized Group Design with four treatments, namely P1 (1), P2 (3), P3 (5), and P4 (7 thrips/container cup). Each treatment was repeated three times (12 experimental units), and each experimental unit used five test leaves. The variable observed was the accuracy of assessing thrips attack intensity on chili leaves based on visual observation and image processing. The results show that high thrips populations can cause high attack intensity on chili plants based on visual observation results, while based on image processing, it is known that high thrips populations do not necessarily cause high attack intensity. The assessment of attack intensity based on visual observation provides a lower accuracy level than image processing. The results of the assessment of attack intensity based on visual observations are less reliable because there is a bias of 0.67.

Evaluation of a neonicotinoid alternative to phorate for the management of soil insects in Florida sugarcane

Wireworms (Coleoptera: Elateridae) are the main soil insect pests of sugarcane (Saccharum spp. hybrids) in Florida. Melanotus communis (Gyllenhal) is the most abundant wireworm in Florida sugarcane fields, reducing stalk populations by feeding on buds of sugarcane seed pieces and on young sugarcane plants. At-planting use of the organophosphate insecticide phorate is the main wireworm management tactic in Florida; however, phorate is a hazardous and relatively expensive insecticide. Thiamethoxam is a neonicotinoid insecticide that has potential to become registered for use on sugarcane in the United States. Previous studies suggested that thiamethoxam decreases wireworm injury to sugarcane seed pieces but does not increase wireworm mortality. The present study conducted between 2018 and 2022 aimed to comprehensively evaluate thiamethoxam for wireworm control under laboratory, outdoor, and field conditions. In two laboratory bioassays, M. communis mortality associated with thiamethoxam (3–20%) was not different than mortality for the non-treated check (0–7%), whereas mortality associated with phorate attained 93–100%. In three large container experiments conducted outdoors with controlled M. communis infestations, thiamethoxam and phorate generally protected young sugarcane plant populations at comparable levels. Insecticide efficacy was mainly associated with the protection of seed-piece buds. However, the number of recovered live wireworms was 2.7–8.0 times greater in thiamethoxam treatments than in phorate treatments. In three field experiments, young sugarcane plant populations in thiamethoxam- and phorate-treated plots were not different than those in non-treated plots. However, the at-planting application of thiamethoxam decreased the number of sugarcane thrips, Fulmekiola serrata (Kobus), by 67–89% in two experiments with thrips infestations 12 weeks after planting. Although the evaluation of insecticide efficacy under natural wireworm infestations was inconclusive, this study confirmed that thiamethoxam should be considered as an alternative to phorate if registered. However, the long-term effects of low wireworm mortality associated with thiamethoxam use should be studied.

Epidemiology and Economic Impact of Impatiens Necrotic Spot Virus: A Resurging Pathogen Affecting Lettuce in the Salinas Valley of California.

The Orthotospovirus impatiens necrotic spot virus (INSV) is a thrips-transmitted pathogen of lettuce that has rapidly emerged as a serious threat to production in the Salinas Valley of Monterey County, California. As a first step toward understanding the severity of the virus, we utilized Spatial Analysis by Distance IndicEs (SADIE) to characterize the distribution and progression of INSV outbreaks and thrips infestations in two commercial lettuce fields. In both fields, INSV incidence rapidly increased from 15.86% ± 1.77 to 80.24% ± 2.60 over the course of 7 weeks and aggregated at specific edges in both fields as early as 3 weeks after planting (Ia = 1.63, Pa = 0.0100, and Ia = 1.53, Pa = 0.0300). In one of the fields, thrips populations aggregated in areas that also experienced the most INSV (Ia = 1.2435, Pa = 0.0400, week 3; Ia = 1.4815, Pa < 0.0001, week 6; Ia = 1.5608, Pa < 0.0001, week 9), while in the second field, thrips were distributed randomly despite the aggregated effects that were observed for INSV incidence. Economic analysis estimated that the virus accounted for over $475,000 in losses for the two fields, while stakeholder surveys documented over 750 fields that experienced INSV infection during the 2021 season in Monterey County alone. These studies enhance our knowledge on the epidemiology of thrips and INSV under current lettuce production practices in the Salinas Valley, while elucidating the economic consequences and broader challenges that are associated with managing thrips-transmitted viruses.

Whether curse or blessing: A counterintuitive perspective on global pest thrips infestation under climatic change with implications to agricultural economics

The improvement and application of pest models to predict yield losses is still a challenge for the scientific community. However, pest models were targeted chiefly towards scheduling scouting or pesticide applications to deal with pest infestation. Thysanoptera (thrips) significantly impact the productivity of many economically important crops worldwide. Until now, no comprehensive study is available on the global distribution of pest thrips, as well as on the extent of cropland vulnerability worldwide. Further, nothing is known about the climate change impacts on these insects. Thus the present study was designed to map the global distribution and quantify the extent of cropland vulnerability in the present and future climate scenarios using data of identified pest thrips within the genus, i.e., Thrips, Frankliniella, and Scirtothrips. Our found significant niche contraction under the climate change scenarios and thrips may reside primarily in their thermal tolerance thresholds. About 3,98,160 km2 of cropland globally was found to be affected in the present scenario. However, it may significantly reduce to 5530 Km2 by 2050 and 1990 km2 by 2070. Further, the thrips distribution mostly getting restricted to Eastern North America, the North-western of the Indian sub-continent, and the north of Europe. Among all realms, thrips may lose ground in the Indo-Malayan realm at the most and get restricted to only 27 out of 825 terrestrial ecoregions. The agrarian communities of the infested regions may get benefit if these pests get wiped out, but on the contrary, we may lose species diversity. Moreover, the vacated niche may attract other invasive species, which may seriously impact the species composition and agricultural productivity. The present study findings can be used in making informed decisions about prioritizing future economic and research investments on the thrips in light of anticipated climate change impacts.

First report of invasive thrips, Thrips parvispinus (Karny) infestation on chilli from Eastern part of India

The South East Asian thrips, Thrips parvispinus (Karny) was first reported in India on Papaya in 2015 later it spread to many host plants such as cowpea, Dahlia rosea, cotton etc. The severe infestation on chilli was reported from southern states during last two years and the extent of loss was more than 50 percent. Therefore, a quick roving survey was conducted to monitor the thrips infestation in chilli at farmer fields of Varanasi and Mirzapur districts of Uttar Pradesh, India. The molecular barcoding of thrips infesting chilli at Varanasi and Mirzapur district of Uttar Pradesh confirmed to be the species as Thrips parvispinus. Therefore, it’s a first report of extended distribution to eastern part of India (Uttar Pradesh). The average number of thrips per three leaves and per flower was 9.1 and 3.1 in Varanasi while in Mirzapur it was 9.3 and 5.1 respectively. The T. parvispinus attained pest status in eastern part of India. The neighbor joining tree indicated certain level of genetic diversity in the species reported from different host plants. Farmers complained about severe crop loss and failure of many insecticides to control them, it may be attributed insecticide resistance