Biology subjects

Firake, D. M.

Publications and source records attributed to Firake, D. M..

5 recordsLinked to original sources

bioRxiv2025

Deciphering the Population Ecology of Blossom Midge, Contarinia maculipennis Felt: An Emerging Threat to Tuberose Cultivation in India

The blossom midge Contarinia maculipennis is a devastating pest of ornamental and vegetable crops, yet its population ecology remains poorly understood. This study employs an age-stage two-sex life table model to analyze its life history with additional focus on below-ground soil environment. Tuberose (Agave amica), a newly identified host, was selected for study. The average fecundity of C. maculipennis was 39.13 eggs, with an intrinsic rate of increase (r) of 0.137, and a mean generation time (T) of 19.73 days. The population doubling time was 5.05 days, with the highest survival rate observed in the first instar larvae (0.95), and the lowest in the adult stage (< 0.38). The population doubling time was 5.05 days. Survival was highest in first-instar larvae (0.95) and lowest in adults (< 0.38). Life expectancy peaked at age zero (e0 =15.57 days) and decreased with pivotal age. The reproductive value (Vx) peaked between 13 and 19 days post-field appearance. Pupal development was fastest, with a significantly higher adult-emergence recorded in sandy clay loam soil (9.67 days); however pupal development and adult-emergence were severely impacted in black cotton and marshy soils. Moderate soil moisture (20%) favored pupation and eclosion rate, while dry (10%) and saturated (30%) soils hindered pupation and emergence. Population projections over 90 days, starting with 133 eggs, estimated an adult population of 3,80738. These findings highlight pupal and adult stages as critical targets for management. Soil type and moisture strongly influence population dynamics, with strategies such as maintaining dry conditions between rows, deep ploughing to bury pupae, and mass trapping recommended for effective control. These insights offer practical strategies for the sustainable management of C. maculipennis.

ecology↗

bioRxiv2024

New Record of Four Thrips Species Infesting Flower Buds of Magnolia champaca in India

The golden-flowered, highly fragrant local variety of Magnolia champaca, known as Sonchafa, is very popular loose flower crop in Maharashtra and adjoining states of India. In response to the rising thrips problems in Sonchafa (M. champaca) fields leading to significant economic losses, we looked into the thrips species composition infesting the plant in the Western Maharashtra region of India. Four thrips species were newly recorded as pests, including Psephenothrips machili (Moulton), Thrips florum Schmutz, Thrips hawaiiensis (Morgan) and Thrips orientalis (Bagnall). Among these, P. machili was identified as the dominant species, responsible for 63% to 71% of bud damage across various fields. This study also marks the first report of an anthophilous host association of P. machili with M. champaca, causing significant economic damage. The observed damage symptoms include, the typical distortion of flower tissues and buds, black spots on buds were ascribed to P. machili. The other three species were found in groups and caused silvery streaks on early-stage buds. The diagnostic characteristics of all the reported species are provided here, accompanied by photomicrographs.

zoology↗

bioRxiv2024

Grey Pineapple Mealybug, Dysmicoccus neobrevipes Beardsley: A New Devastating Pest of Tuberose in India

Tuberose (Agave amica) is a highly valued flower crop in India, known for its consistently high returns and ability to thrive in various climatic conditions. Severe outbreaks of the grey pineapple mealybug, Dysmicoccus neobrevipes Beardsley (Hemiptera: Pseudococcidae), have been observed in several villages of the Pune district, Maharashtra (India), since 2021, leading to significant economic losses. This report provides an illustrative morphological diagnosis of D. neobrevipes and basic information on its field establishment, impact on tuberose crops, nature of the damage and field symptoms etc. Surveys conducted in major tuberose-growing areas of Pune district (Maharashtra) revealed that the mealybug primarily infests the underground and basal portion of tuberose plants, causing stunted growth, drooping, and ultimately death of the plants. D. neobrevipes produces honeydew, fostering sooty mold growth that impairs photosynthesis, reduces flower yield. It also infests tuberose bulbs, spoiling them in storage. Based on primary scientific literature, this study represents the first scientifically confirmed record of D. neobrevipes as a new pest of tuberose in India. The ant species Solenopsis geminata was found attending to mealybug colonies, aiding their spread and creating a nuisance for farmers during routine field activities. A total of 87.09% of the surveyed fields (n=62) showed mealybug infestation, ranging from 68% to 97%. Raising awareness among the farmers and implementing regular monitoring in tuberose-growing areas are crucial steps for developing effective management practices and preventing the further spread of this pest to other regions.

zoology↗

bioRxiv2023

Eggplant's chlorogenic acid provides resistance against the tropical armyworm

Lepidopteran pests are the major crop devastators. Farmers have to resort to heavy synthetic pesticide application for their control. It increases the pesticide residue contamination on produce and causes health hazards. Synthetic pesticides also endanger beneficial insects and pollute the environment. Therefore, the use of safe and eco-friendly botanicals as biopesticides is rapidly increasing. Despite their high demand, only a few botanicals are commercially available. Consequently, biopesticide discovery research boomed in the last decade. Spodoptera litura Fabricius (armyworm) is a polyphagous multi-insecticide-resistant lepidopteran pest. It is a serious concern for several commercially important crops. In this study, we employed a chemical ecology approach to discover a biopesticide against it. As a biopesticide source, we explored secondary metabolite-rich Solanum melongena L. (eggplant), one of the armyworms hosts. We found that the armyworm larvae show differential occurrence on seven eggplant varieties; the Himalayan eggplant variety RC-RL-22 (RL22) showed no armyworm infestation. When reared in a no-choice condition on RL22, larval mortality was two-fold higher, and mass was three-fold lower than the varieties showing high infestation. We tested whether RL22s secondary metabolite(s) were associated with this hampered larval performance. Using LC-ESI-QTOF-based non-targeted metabolomics of eggplant varieties, we identified candidate metabolites. 5-O-caffeoylquinic acid (chlorogenic acid; CGA) showed a strong negative correlation (r= -0.88; p= 0.008) with the larval performance. CGA-spiked (average physiological concentration) artificial diet (CGA-AD)-fed larvae showed a three-fold mass reduction and two-fold mortality increase than the control artificial diet (AD)-fed larvae; pupation and eclosion also significantly reduced (1.3-fold and 1.4-fold, respectively) in the CGA-ingested larvae. We used a reverse genetics approach to assess the in planta insecticidal potential of CGA. When RL22s CGA biosynthesis gene hydroxycinnamoyl-CoA quinate transferase (SmHQT) was silenced using virus-induced gene silencing (VIGS), CGA levels decreased by three-fold. This CGA depletion rendered RL22 two-fold armyworm-susceptible than controls. Foliar CGA application restored RL22s armyworm resistance. Overall, this study showed that CGA exhibits larvicidal properties against the armyworm. It is also safe for beneficial organisms. CGA is a well-known dietary supplement and an antioxidant for humans. Thus, it is safe for human consumption. Together, high CGA-containing varieties can be used to reduce the armyworm infestation risk. CGA is a promising biopesticide candidate for the field trial phase against the lepidopteran pests, especially armyworm. If successful, it can be integrated into the pest control measures.

plant biology↗

bioRxiv2022

Chemical ecology of Himalayan eggplant variety's antixenosis: Identification of geraniol as an oviposition deterrent against the eggplant shoot and fruit borer

O_LIEggplant (Solanum melongena) suffers severe losses due to a multi-insecticide resistant lepidopteran pest, shoot and fruit borer (SFB, Leucinodes orbonalis). Heavy and combinatorial application of pesticides for SFB control renders eggplant risky for human consumption. C_LIO_LIWe observed that 1) ovipositing SFB females can find even solitary plants of susceptible varieties and 2) they do not oviposit on Himalayan eggplant variety RC-RL-22 (RL22). We hypothesized that the olfactory cues influence ovipositing females host choice. C_LIO_LITo find these cues, leaf volatile blends of seven eggplant varieties were profiled using GCMS. Seven compounds were present in >2.5-fold concentrations in RL22 than the other varieties. In choice assays, oviposition deterrence efficacies of these candidate compounds were independently tested by their foliar application on SFB-susceptible varieties. Complementation of geraniol, which was exclusively found in RL22, reduced oviposition (>90%). To validate geraniols role in RL22s SFB-deterrence, we silenced RL22s geraniol synthase gene using virus-induced gene silencing. Geraniol biosynthesis suppression rendered RL22 SFB-susceptible; foliar geraniol application on the geraniol synthase-silenced plants restored oviposition deterrence. C_LIO_LIWe infer that geraniol is RL22s SFB oviposition deterrent. The use of natural compounds like geraniol, which influence the chemical ecology of oviposition can reduce the load of hazardous larvicidal pesticides. C_LI

plant biology↗