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    Pests of exotic fruit crops in Kerala
    (Department of Entomology, College of Agriculture, Vellayani, 2024-02-27) Akheela, P; Thanima Sara Varghese
    The study entitled “Pests of exotic fruit crops in Kerala.” was conducted at the Department of Entomology, College of Agriculture, Vellayani from 2021 to 2023 with the objective of documenting the pests of exotic fruits, its natural enemies and pollinators in Kerala. The documentation was carried out at the orchard of Instructional Farm, Vellayani and in farmer’s field in Thiruvananthapuram, Kollam, Kottayam and Malappuram districts of Kerala through multiple field visits. A total of 60 different pests were documented from different exotic fruit crops. Among them, 32 pests were documented from rambutan Nephelium lappaceum (L.), 8 from dragon fruit Selenicereus undatus (Haw.) D. R. Hunt, 7 from mangosteen Garcinia mangostana (L.), 4 from passion fruit Passiflora edulis (Sim.), and 10 from other minor exotic fruit crops like miracle fruit Synsepalum dulcificum (Schumach. and Thonn.), pulasan Nephelium mutabile (Blume.), abiu Pouteria caimito (Radik.), soursop Annona muricata (L.), litchi Litchi chinensis (Sonn.), velvet apple Diospyros discolor (Willd.) and longan Dimocarpus longan (Lour.). Leaf and inflorescence caterpillars were predominant in rambutan followed by sucking pests and beetles. The sucking pests include, mealybug Planococcus lilacinus (Cockerel), Crisicoccus hirsutus (Newstead), Ferrisia virgata (Cockerell), scale Ceroplastis floridensis (Comstock), Icerya sp., bean bug Riptortus pedestris (Fabricius), cow bug Otinotus oneratulus (Walker), tree hopper Gargara sp., black plant hopper Ricania sp., flatid plant hopper Flatormenis sp. The lepidopterans recorded in rambutan were white looper moth Pingasa chlora (Stoll), slate flash Rapala manea (Hewitson), emerald moth Hemithea tritonaria (Walker), yellow-tail tussock moth Somena scintillans (Walker), tussock caterpillar Olene mendosa (Huebner), looper Comibaena cassidara (Guenee), pointed ciliate blue Anthene lycaenina (Felder), owl moth Avatha discolor (Fabricius) and a bark borer which is an unidentified micro lepidopteran. Scarab beetle Popillia sp., warty leaf beetle Exema salemensis (Bhasin), leaf beetle Monolepta sp. and flower beetle Oxycetonia versicolor (Fabricius) were the coleopteran pests documented on rambutan. Rambutan was identified as the host for the above-mentioned pests for the first time in India. In dragon fruit, the oriental fruit fly Bactrocera dorsalis (Hendel) was reported for the first time in India. The sucking pests like the brown stink bug Halyomorpha picus (Fabricius), plant hopper Eurybrachis sp., Ricania sp. and Flatormenis sp., striped mealybug Ferrisia virgata (Cockerell), and a destructive trailing ant Trichomyrmex destructor (Jerdon) were also reported for the first time as insect pests of dragon fruit from India. Pest infestation was comparatively lower in mangosteen and passion fruit. The brown soft scale Coccus hesperidum (Linnaeus), mealybug C. hirsutus, leaf eating caterpillar Agrotera flavobasalis (Inoue) and flower feeding caterpillar Homona sp. were reported for the first time in mangosteen from India. The rugose spiralling whitefly Aleurodicus rugioperculatus (Martin) and gold tail moth Sphrageidus xanthorrhoea (Kollar) were reported for the first time in passion fruit from India. Biology of B. dorsalis, H. picus and S. xanthorrhoea were studied under laboratory condition. The egg, larval, pupal and adult period of male, female B. dorsalis in dragon fruit were 1.6± 0.40, 8.0 ± 0.40, 8.0 ± 0.31, 6.4 ± 0.50 and 9.6 ± 0.5 days respectively. The egg, larval and pupal period of S. xanthorrhoea 5.2 + 0.20, 25.6 ± 1.20, 6.6 ± 0.37 days respectievely. Adult period of male and female were 4.4 ± 0.24 and 6 ± 0.44 days respectively. The egg and nymphal periods for H. picus were 5.2 ± 0.20 and 46.8 ± 2.53 days, respectively. Spiders were the dominant predators of the pests of exotic fruits. A total of 24 natural enemies were documented from exotic fruit crops, which include spiders (15), hymenopteran parasitoids (3) and insect predators (6) belonging to Coleoptera (1), Lepidoptera (1), Mantodea (3) and Hemiptera (1). The hymenopteran parasitoids documented were from the family Eupelmidae, Aphelinidae and Trichogrammatidae. For the documentation of pollinators, a study was conducted during the flowering season of rambutan and passion fruit at Instructional Farm Vellayani. For documentation of pollinators of rambutan, five inflorescences each were selected randomly from five different trees. Population of pollinators was recorded by visual observation once in a week from 0600 to 1800 h for a period of four weeks. For documentation of pollinators of passion fruit, the same methodology was adopted for plant selection and pollinators were recorded once in four weeks from 1200 to 1800 h for a period of four weeks. Ten pollinators were recorded from rambutan and four were from passion fruit. The pollinators documented belong to Hymenoptera (9) Diptera (3) and Lepidoptera (2). Stingless bee Tetragonula travancorica (Shanas and Faseeh) was the most abundant and frequent flower visitor of rambutan and carpenter bee (Xylocopa sp.) was the frequent visitor of passion fruit flowers. Seasonal incidence of pests infesting rambutan was carried out for one year from November 2022 to November 2023. The presence of pests in rambutan was noted specifically from March to July, encompassing the flowering to fruit-setting season. The peak pest infestation had a positive correlation with the temperature in rambutan. In the course of the current investigation, a comprehensive catalogue of 60 pests, 24 natural enemies, and 14 pollinators were documented from exotic fruits in Kerala. Among the identified pests 27 pests were recorded from the order Hemiptera, 21 from Lepidoptera, 6 from Coleoptera, 4 from Hymenoptera and 2 from Diptera. Rambutan has been documented to have 14 pests from the order Lepidoptera, 11 from Hemiptera, 5 from Coleoptera, and 2 from Hymenoptera. Dragon fruit pests include 5 from Hemiptera, 1 from Lepidoptera, 1 from Diptera, and 1 from Hymenoptera. Mangosteen pests belong to the order Hemiptera (3), Lepidoptera (3), and Hymenoptera (1). Passion fruit pests include 2 from Hemiptera, 1 from Lepidoptera, and 1 from Diptera. Minor exotic fruits have pests from Hemiptera (6), Lepidoptera (3), and Coleoptera (1).Spiders emerged as the predominant predators associated with the exotic fruit pests. Hymenopteran pollinators stood out as the most abundant contributors to pollination where stingless bee (T. travancorica) was the most abundant and frequent flower visitor of rambutan and carpenter bee (Xylocopa sp.) was the frequent visitor of passion fruit flowers. The pest incidence in rambutan showed a positive correlation
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    Compatibility of herbicides and insecticides for tank mix application in wet seeded rice
    (Department of Agronomy, College of Horticulture, Vellanikkara, 2017) Anjana Devaraj, G; Prameela, K P
    Weeds and insect pests are the major biotic constraints in rice production. Chemical methods of control of insects as well as weeds is very common in rice production. Separate application of the chemicals is expensive and labour intensive with the result that many farmers of Kerala adopt tank mix application of different chemicals without due consideration to efficacy and compatibility. The present study entitled “compatibility of herbicides and insecticides for tank mix application in wet seeded rice” was conducted in a farmer’s field at Alappad Kole lands of Thrissur district, from August 2016 to January 2017. The experiment aimed at studying the compatibility of two commonly used herbicides (bispyribac sodium and cyhalofop-butyl) with two new generation insecticides (flubendiamide and imidacloprid) for tank mix application in wet seeded rice. Another objective of the study was to assess the pest control efficiency of herbicides and insecticides. Out of 14 treatments, four treatments in the trial included sequential and mixed application of bispyribac sodium with two insecticides separately. The next four included cyhalofop-butyl substituted for bispyribac sodium. The remaining treatments were application of herbicides alone, hand weeding with and without application of insecticides and unweeded control. Weed spectrum of the experimental field included barnyard grass (Echinochloa crus-galli), hippo grass (Echinochloa stagnina) and red sprangletop (Leptochloa chinensis) among grasses. Major broad leaf weed was water primrose (Ludwigia parviflora). Yellow nut sedge (Cyperus iria) was the only sedge species which was the major weed of the experimental plot. Treatments were studied for their phytotoxic effects on rice and no toxicity symptoms were observed in tank mix or sequential application. Weed counts, weed dry matter production and weed control efficiency were estimated at different stages of crop growth. Comparing sequential application and tank mix application of bispyribac sodium and flubendiamide, the mixed application resulted in high weed dry weight and low weed control efficiency. Yield parameters and yield were recorded low in this treatment. For sequential and combined applications of bispyribac sodium and imidacloprid, weed control efficiency, weed dry weight, yield and yield attributes were on par. Weed dry weight was low and weed control efficiency was high for mixed application of cyhalofop-butyl and flubendiamide. Yield and yield attributes were also high for this treatment. Weed dry weight, weed control efficiency, yield attributes and yield were comparable for sequential and mixed applications of cyhalofop-butyl and imidacloprid. Insect pest infestation was very low in the experimental field. Rice leaf folder (Cnaphalocrocis medinalis), white backed plant hopper (Sogatella furcifera), red spotted earhead bug (Menida versicolor) and yellow stem borer (Scirpophaga incertulas) were the insect pests noted. Observation on insect count showed that there was no significant difference among treatments with respect to insect pest counts at 5, 7 and 11 days after spraying which was comparable to unweeded control. Hence efficacy of insecticides when tank mixed with herbicides could not be interpreted. Hand weeding was the best treatment in terms of weed control efficiency, yield and yield attributes. However, the highest B: C ratios were registered by the treatments cyhalofop-butyl + flubendiamide and bispyribac sodium + imidacloprid. Highest net return was recorded in bispyribac sodium + imidacloprid. Unweeded control recorded lowest values for yield and B: C ratio. With respect to efficacy of herbicides used, the study indicated that the two insecticides tried were compatible with cyhalofop-butyl. In the case of bispyribac sodium, the insecticide imidacloprid appeared to be compatible, but mixing of flubendiamide cannot be recommended since weed control efficiency was very low.