Timing of oomycete-specific fungicide application impacts the efficacy against fruit rot disease in arecanut

Fungicidal application has been the common and prime option to combat fruit rot disease (FRD) of arecanut (Areca catechu L.) under field conditions. However, the existence of virulent pathotypes, rapid spreading ability, and improper time of fungicide application has become a serious challenge. In the present investigation, we assessed the efficacy of oomycete-specific fungicides under two approaches: (i) three fixed timings of fungicidal applications, i.e., pre-, mid-, and post-monsoon periods (EXPT1), and (ii) predefined different fruit stages, i.e., button, marble, and premature stages (EXPT2). Fungicidal efficacy in managing FRD was determined from evaluations of FRD severity, FRD incidence, and cumulative fallen nut rate (CFNR) by employing generalized linear mixed models (GLMMs). In EXPT1, all the tested fungicides reduced FRD disease levels by >65% when applied at pre- or mid-monsoon compared with untreated control, with statistical differences among fungicides and timings of application relative to infection. In EXPT2, the efficacy of fungicides was comparatively reduced when applied at predefined fruit/nut stages, with statistically non-significant differences among tested fungicides and fruit stages. A comprehensive analysis of both experiments recommends that the fungicidal application can be performed before the onset of monsoon for effective management of arecanut FRD. In conclusion, the timing of fungicidal application based on the monsoon period provides better control of FRD of arecanut than an application based on the developmental stages of fruit under field conditions

Concurrent emergence of exotic whitefly incursions on arecanut (Areca catechu L.) in India

Field incidence of exotic whitefly complex comprising two Neotropical nesting whiteflies viz., Paraleyrodes bondari Peracchi and Paraleyrodes minei Iaccarino, in association with invasive rugose spiralling whitefly Aleurodicus rugioperculatus Martin and native areca whitefly, Aleurocanthus arecae David & Manjunatha, on arecanut was reported from Karnataka, India during 2020. These arecanut palms were previously infested by A. arecae which was earlier reported from Karnataka during 2003. To our knowledge, this is the first report on the infestation of P. bondari and P. minei on arecanut as highlighted in this current investigation. Morphological identification based on pupal taxonomy and male genitalia as well as molecular characterization of the mitochondrial cytochrome oxidase I (COI) gene confirmed the identity of nesting whiteflies. The Bondar’s nesting whitefly, P. bondari is the most predominant whitefly species with 87.5 per cent active colonies followed by the nesting whitefly, P. minei (13.64%) and the rugose spiralling whitefly, A. rugioperculatus (6.25%). Co-occurrence of these three non-native whitefly species on arecanut in synergy with the native A. arecae indicates a kind of competitive regulation of one species over the other upsetting biodiversity. Due to the polyphagous nature of the pest coupled with increased trade and transport in a climate change scenario, this whitefly complex may become a serious threat to arecanut production in India and elsewhere. This requires strict quarantine protocols to avert its spread to other arecanut growing areas

Xylosandrus crassiusculus (Motschulsky) (Coleoptera: Curculionidae) and Its Fungal Symbiont Ambrosiella roeperi Associated with Arecanut Kernel Decay in Karnataka, India

Xylosandrus crassiusculus (Coleoptera: Curculionidae: Scolytinae) is reported causing damage to areca palm plantations (Areca catechu L.—Arecaceae) in Karnataka (India). In particular, X. crassiusculus has been observed attacking and successfully reproducing on areca nuts; besides the new host plant record, the data provided here represent the first documented case of spermatophagy for this xyleborine beetle. All infestation symptoms of this polyphagous pest were documented and illustrated. The identity of the scolytid, besides morphologically, was confirmed by its DNA barcoding. Eggs, larvae and pupae were found within the galleries of infested kernels. All galleries of the infested kernels were characterized by the presence of whitish to greyish fungal growth. The fungus was identified as Ambrosiella roeperi, a known symbiont of Xylosandrus crassiusculus. Incidence of this symbiotic insect-fungus complex in the economic part of arecanut, i.e., the kernel, is of serious concern. In a climate change scenario, this beetle with fungal symbionts may pose a serious threat to arecanut production in India and elsewhere

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Not AvailableNot AvailableDirectorate of Cashew and cocoa development, Cochi

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Not AvailableThe present investigation was conducted to study the lethal effect of insecticides recommended for management of tea mosquito bug, Helopeltis spp. on bio-control agent, Trichoderma harzianum. Effect of six insecticides (Bifenthrin 10% EC, Clothianidin 50% WDG, Flonicamid 50% WG, Imidacloprid 17.8% SL, Thiamethoxam 25% WG and Quinalphos 25% EC) with three doses (lower, recommended and higher) on colony growth, antagonism potential and sporulation of Trichoderma harzianum were studied. Quinalphos 25% EC showed high inhibitory effect in all three doses. Recommended dose of Quinalphos caused 72.77, 58.18 and 97.16 per cent reduction in mean colony growth, antagonism potential and sporulation of Trichoderma harzianum respectively. Slight deleterious effect in highest dose (150 ppm) of Bifenthrin 10% EC was recorded with 13.33, 5 and 9.83 percent inhibition in mean colony growth, antagonism potential and sporulation respectively. All other insecticides under investigation were found non toxic at all three doses and were at par with control which indicated the compatibility of these insecticides with Trichoderma harzianum. All the compatible insecticides can be utilized in Integrated Pest Management programme with recommended doses along with Trichoderma harzianum without causing any deleterious effect.Not Availabl

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Not AvailablePresent study was carried to access the major storage insect pests complex of arecanut, a survey was carried out in 30 different arecanut godowns at coastal region of Karnataka during May, 2017. Among the major storage insect pests recorded, flat grain beetle Cryptolestes pusillus (Schönherr) was most serious with 58.33 per cent infestation followed by cigarette beetle Lasioderma serricorne (Fabricius) with 21.74 per cent infestation, palm seed borer Coccotrypes carpophagus (Hornung) with 13.58 per cent infestation, coffee bean weevil Araecerus fasciculatus with 5.34 per cent infestation (DeGeer) and red flour beetle Tribolium castaneum with 0.9 per cent infestation (Herbst). Grade wise (fresh nuts = less than one year old stored nuts; single chole = more than one year old stored nuts; double chole = more than two year old stored nuts; and patora = cracked nuts of one year old storage) per cent damage of insect pests were also recorded during this study. Highest per cent damage recorded in patora (45 per cent) followed by fresh nuts (35.22 per cent), double chole (25.55 per cent) and single chole (14 per cent). Predatory anthocorid bug Xylocoris flavipes feeding on different stages of flat grain beetle Cryptolestes pusillus was recorded during study.Not Availabl

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Not AvailableNot AvailableDirectorate of Cashewnut and Cocoa Development (DCCD), Koch

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