Kerala Agricultural University, Thrissur

The history of agricultural education in Kerala can be traced back to the year 1896 when a scheme was evolved in the erstwhile Travancore State to train a few young men in scientific agriculture at the Demonstration Farm, Karamana, Thiruvananthapuram, presently, the Cropping Systems Research Centre under Kerala Agricultural University. Agriculture was introduced as an optional subject in the middle school classes in the State in 1922 when an Agricultural Middle School was started at Aluva, Ernakulam District. The popularity and usefulness of this school led to the starting of similar institutions at Kottarakkara and Konni in 1928 and 1931 respectively. Agriculture was later introduced as an optional subject for Intermediate Course in 1953. In 1955, the erstwhile Government of Travancore-Cochin started the Agricultural College and Research Institute at Vellayani, Thiruvananthapuram and the College of Veterinary and Animal Sciences at Mannuthy, Thrissur for imparting higher education in agricultural and veterinary sciences, respectively. These institutions were brought under the direct administrative control of the Department of Agriculture and the Department of Animal Husbandry, respectively. With the formation of Kerala State in 1956, these two colleges were affiliated to the University of Kerala. The post-graduate programmes leading to M.Sc. (Ag), M.V.Sc. and Ph.D. degrees were started in 1961, 1962 and 1965 respectively. On the recommendation of the Second National Education Commission (1964-66) headed by Dr. D.S. Kothari, the then Chairman of the University Grants Commission, one Agricultural University in each State was established. The State Agricultural Universities (SAUs) were established in India as an integral part of the National Agricultural Research System to give the much needed impetus to Agriculture Education and Research in the Country. As a result the Kerala Agricultural University (KAU) was established on 24th February 1971 by virtue of the Act 33 of 1971 and started functioning on 1st February 1972. The Kerala Agricultural University is the 15th in the series of the SAUs. In accordance with the provisions of KAU Act of 1971, the Agricultural College and Research Institute at Vellayani, and the College of Veterinary and Animal Sciences, Mannuthy, were brought under the Kerala Agricultural University. In addition, twenty one agricultural and animal husbandry research stations were also transferred to the KAU for taking up research and extension programmes on various crops, animals, birds, etc. During 2011, Kerala Agricultural University was trifurcated into Kerala Veterinary and Animal Sciences University (KVASU), Kerala University of Fisheries and Ocean Studies (KUFOS) and Kerala Agricultural University (KAU). Now the University has seven colleges (four Agriculture, one Agricultural Engineering, one Forestry, one Co-operation Banking & Management), six RARSs, seven KVKs, 15 Research Stations and 16 Research and Extension Units under the faculties of Agriculture, Agricultural Engineering and Forestry. In addition, one Academy on Climate Change Adaptation and one Institute of Agricultural Technology offering M.Sc. (Integrated) Climate Change Adaptation and Diploma in Agricultural Sciences respectively are also functioning in Kerala Agricultural University.

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Open Access
Biology and biometry of Neochetine elchhorniae warner (Curculionidae: Coleoptera) and the nature of damage caused by it on Eichhornia crassipes (mart)
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 1990) Sreekumar, K M; KAU; Joseph, D
The biology, morphology, biometrics and dispersal pattern of the weevil Neochetina eichhorniae Warner and the nature and extent of damage caused by it on water hyacinth (Eichhornia crassipes (Mart.) were studied. An indirect method of estimating the field population was also attempted. The insect laid the eggs beneath the epidermis of plant parts. Incubation period was 6.6 days and the hatching percentage was 93.2. The larvae fed by tunnelling, and the first, second and third larval instars were completed in 8-10, 13-16 and 13-17 days, respectively. The cocoon was attached to the live roots of the plant and the pupation was just below the water surface. The pupal period was 16.6 days. Adult female longevity was 75.3 days while that of the male was 172.3 days. Pre-oviposit iona I period was 49 days and the total number of eggs produced during the whole life period was 462.5. The head capsule width of first, second and third instar larvae were 0.3, 0.488 and 0.693 mm respectively. In adult males, the average distance between the antennal socket and the tip of the rostrum was 0.259 mm and it was 0.487 mm in females. This character helps in the identification of sexes. No microbes or mites were recorded as natural enemies. The predators were the common non-specific aquatic insects like dytiscid beetle, giant water bug, dragon fly naiads and back swimmers.
Open Access
Biology and Population Build up of the Rice Whitebacked Planthopper, Sogatella furcifera (Horvath) on Different Rice Varieties
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 1990) Ajith, P P; KAU; Madhavan Nair, G
Investigations were carried out in the College of Agriculture, Vellayani during 1988 to identify cultivars resistant to the white backed planthopper, S. furcifera from among the high yielding rice varities commonly cultivated in Kerala. The rice cultivars Cul 126, Cul 93, Ptb 33, Karthika, Pavizham, Jyothi, Triveni and TN-1 were chosen for preliminary screening by seed box screening, free-choice and no-choice tests and by tests on orientation and settling response and population build up. In the seed box screening and free choice and no choice tests, the cultivar Cul 126 recorded the lowest damage and the cultivar TN-1 showed the highest damage, indicating resistance in the former and susceptibility in the latter. The cultivar Jyothi did not differ from Cul 126 and the cultivars Cul 93, Ptb 33, Pavizham and Karthika showed intermediate levels of resistance. In the orientation and settling response test the highest number of S. furcifera nymphs were seen settled on TN-1, where as it was the lowest on Cul 126 and it was followed by Jyothi, indicating a clear preference to the susceptible TN-1. The insect multiplied faster and in greater number on TN-1 and the total count was about thirty times more on TN-1 as compared to that on Cul 126 at 60 days after release. Based on the results of the preliminary screening trials, the cultivar Cul 126 and Jyothi (resistant), Pavizham and Karthika (moderately resistant) and TN-1 (susceptible check) were selected for studying the mechanisms of resistance. In the experiment to study the ovipositional preference of the insects it was found that the susceptible TN – 1 and the resistant Cul 126 received the highest and lowest number of eggs respectively. It was also revealed that the leaf sheath received more eggs than the leaf blade. The antibiosis factor in the cultivars was investigated in terms of nymphal duration, nymphal survival, sex ratio of emerging adults, adult longevity, fecundity and hatching percentage of eggs in three growth stages of plants, namely, seedling, tillering and booting stages. The insects from the susceptible TN – 1 had the shortest nymphal duration and the longest adult longevity. The percentage of nymphal survival, fecundity and female/male ratio of the emerging adults were also the highest on TN -1. However, the insects from Cul 126, and Jyothi had longer nymphal duration and shorter adult longevity. The survival, fecundity and female/male ratio of the emerging adults from these cultivars were also lower as compared to TN – 1. The results were uniform in all the three growth stages of the crop. No difference could be observed in the hatching percentage of eggs in the test cultivars in the seedling stage, but in the tillering and booting stages the eggs on TN – 1 showed higher hatching percentage. The results indicated the presence of antibiosis factor in the resistant cultivars, Cul 126 and Jyothi. These results were further confirmed in the experiment on the feeding rate of the insect on the test cultivars. Insects on TN-1 produced the largest area of honey dew spots as compared to others in all the three growth stages showing significantly higher feeding rates. The feeding rate in Cul 126 was the lowest. The effect of crowing of first instar nymphs was more pronounced on the insects on TN-1. The survival percentage was the maximum in crowing at the rate of 25 and it dwindled substantially in the susceptible and resistant cultivars alike in crowding at the rate of 100. Crowding did not have any effect on the sex ratio and brachyptery of emerging adults. When S. furcifera and N. lugens were released together in different proportions, the latter surpassed the former in total number in all the cultivars when counts were taken at 60 days after release of the insects. The result indicated that in cultivars resistant or susceptible to both the insects, N. lugens established a numerical superiority over S. furcifera. In studies to identify the wet land weeds which serve as alternate hosts to S. furcifera, it was found that the insects oviposited in none of the weed plants tested. The nymphs could survive only on Echinochloa colona and Panicum repens.
Open Access
Mass trapping of the sweet potato weevil (Coleoptera: Curculionidae) males using sex pheromone
(Department of Agricultural Entomology, College of Horticulture,Vellanikkara, 1993) Mini, E S; KAU; Sitarama Rao, S
The efficacy of the synthetic pheromone of C. formicarius elegantulus in attracting the males of C. formicarius formicarius was tested in the field. The effect of continuous mass trapping of adult males on the population build up of the pest in the field was assessed. The effect of different doses of pheromone as influenced by the trap designs was also assessed. Low cost traps designed and fabricated out of locally available materials were tested in the field and incremental benefit of treatments was worked out. The range of attraction of pheromone doses was assessed by analysing the recapture data of marked males released at different distances from the pheromone baited traps. The results indicated that the weevils were most active during the night as is evidenced by higher capture of weevils at morning observations than those in the evening observations. The weevil catch was not significantly influenced by the higher doses of pheromone. Day light affected the flight pattern of weevils while the moon phases have no significant effect. continued attraction of males towards the pheromone baited traps indicated their effectiveness inspite of the presence of virgin females in the field. The pheromone doses were effective in checking the rapid build up of the pest in the field as evidenced by the non reduction in vine weight. Among the three trap designs polythene bag trap was the cheapest one to install and resulted in the most favourable C : B ratio. The attraction of the pheromone doses decreased with increase in the distance of release from the pheromone source. A distance of 25 m was found to be ideal for placement of traps in the field. The cheapness of traps facilitate installation of large number of traps at reasonable increase in cost.
Open Access
Effect of chitin synthesis inhibitors on rice swarming caterpillar spodoptera mauritia and rice moth corcyra cephalonica and a larval parasitoid bracon brevicornis
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 1991) Prathapan, K D; KAU; Dale, D
Effects of four chitin synthesis inhibitors viz. diflubenzuron, chlorfluazuron, PH 70-23 and BASF LAB 153 959 I were assessed on two insect pests, the rice swarming caterpillar Spodoptera mauritia ( Boisduval) and rice moth Corcyra cephalonica (Stainton) and on its larval parasitoid Bracon brevicornis (Wesmael). Ovicidal action was assessed by treating one and two-day old eggs of S. mauritia in aqueous and mathanilic media. It was low in aqueous medium. But in methanolic medium diflubenzuron and the highest doses of the other three compounds showed enhanced action. In general, high ovicidal action was observed in methanolic medium. There was no significant difference between one and two-day old eggs in their susceptibility to chitin synthesis inhibitors. Chlorfluazuron was the most toxic causing cent per cent mortality at doses as low as 2 x 10 -5% when treated on second and fifth instar larvae of S. mauritia. Diflubenzuron, PH 70-23 and BASF LAB 153 959 I were also highly effective. Second instar larvae were more susceptible than fifth instar ones. Besides stomach action, a high degree of contact action was also observed. Final instar larvae of S. mauritia when treated with the test chemicals, produced larval-pupal intermediates and caused pupal mortality and emergence of deformed adults. All the four moult inhibitors were highly active during larval – pupal transformations. Pupae were less susceptible to chitin synthesis inhibitors. Yet, some treatments caused mortality and emergence of deformed adults. Chlorfluazuron was the most toxic to pupae. Fecundity, hatchability of eggs and longevity were reduced when the male moths of S. mauritia were fed on sugar solution containing the moult inhibitors. Antifeedant action of the chitin synthesis inhibitors was found to be less pronounced. Residual effect of all the four compounds persisted on the treated rice foliage throughout a study period of 36 days. But the efficacy of residues exposed to sunlight and rain was very low. Ovicidal action of the moult inhibitors was low to moderate on one and four-day old eggs of C. cephalonica in aqueous medium. In methanolic medium diflubenzuron at 2 x 10 -1 %, 2 x 10 -2 % and 2 x 10 -3 % and PH 70-23 and BASF LAB 153 959 I at 2 x 10 -1 % caused enhanced ovicidal action. In general there was no significant difference between the susceptibility of one and four-day old eggs. Chlorfluazuron was found to be the most toxic compound against larvae of C. cephalonica followed by BASF LAB 153 959 I. Diflubenzuron and PH 70-23 were less effective. Early larval instars were more susceptible. Contact action of compounds other than chlorfluazuron was low. Larval – pupal intermediates, pupal mortality and emergence of deformed adults were resulted when the last instar larvae of C. cephalonica were treated with the chemicals. Chlorfluazuron was found to be the most toxic compound. Prepupal treatment also caused the above juvenomimetic effects. But treatments other than chlorfluazuron 2 x 10 – 2% were less effective. Treatment of pupae of C. cephalonica resulted in pupal mortality and emergence of deformed adults. But pupae were less susceptible to the moult inhibitors as compared to the larval stages. External application of Chitin synthesis inhibitors to moths of C. cephalonica had no adverse had no adverse effect on fecundity, hatchability of eggs and longevity of the treated moths. Chlorfluazuron was found to inhibit the emergence of adult parasites from treated hosts and adversely affect the progeny production of B. brevicornis. Diflubenzuron, PH 70-23 and BASF LAB 153 959 I were non-toxic or only slightly toxic to the parasite.
Open Access
Bioecology of orthogalumna terebrants wallwork on waterhyacinth
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 1994) Babykala, P; KAU; Joy, P J
The mite biology, morphology, nature of extent of damage and interaction with N. eichhorniae were studied. The might laid solitary eggs sideways to the oviposition holes, deeply embedded in the aerenchyma cells. The incubation period was 5.8 days. The larvae and nymphs fed by making galleries. The larvae, proto and deuto nymphal stages were completed in 3 days each, while that of tritonymph took 4 days. The duration of inactive stages from larva to proto, proto to deuto and deuto to tritonymphal stage were 1.6 days each, whereas from tritonymph to adult, it was 3 days. Adult longevity was 57.3 days. pre-ovipositional period was 4 days and the total number of eggs produced during the whole life period was 41.5 eggs. The larvae have three pairs of legs but no genital opening. The nymphal stages have four pairs of legs, ending in single claws. The proto, deuto and tritonymphal stages, have one, two and three pairs of genital papillae respectively. This character helps in identification of larval and nymphal stages. The adults are pteromorphs and sexual dimorphism is absent. Sensillus is relatively short with curved stem and globular roughened head. Terminally the tarsus of the leg has three claws on a short peduncle the lateral claws more slender than the median and sharply angled. The larval and nymphal feeding produces galleries on leaves of waterrhyacinth resulting in brown streaks on the leaf lamina. Such brown streaks later coalesce to form large brown areas, leading to drying up of the entire leaf. As the mite load increased from ten to eighty the number of plants and number of leaves showed significant reduction 90 days after release. The extent of damage caused by O. terebrantis with or without weevil under open and partially shaded conditions of waterhyacinth plants was experimented upon, and it showed that, the root length, petiole length ( in open condition), laminar width and length, number of leaves and number of plants under both light intensities (partially shaded and open condition), in general showed a decreasing trend. The plants in tanks having ten weevils alone per tank and 10 weevils plus 100 mites per tank under partially shaded conditions collapsed within 60 days, whereas in open condition of that having 10 weevils plus 100 mites per tank, all the plants collapsed by the 75th day. In the treatment with ten weevils alone per tank in open condition the collapse occurred only at 105 days. In the treatment with 100 mites alone per tank, there was no collapse of plants upto 105 days (in both conditions). The number of mite galleries and mite population per leaf with Neochetina feeding marks was comparatively more in the presence of weevils than in their absence. Fungi like Fusarium, Aspergillus and Rhizopus were isolated and also the spider mite and insects like aphids and grasshoppers were noticed.
Open Access
Biology of banana pseudostem weevil Odoiporus longicollis Oliv. (Coleoptera : Curculionidae)
(Department of Agricultural Entomology , College of Horticulture, Vellanikkara, 1992) Jayasree, T V; KAU; Jim Thomas
The Banana Pseudostem Weevil, Odoiporus longicollis Oliv., considered as one of the destructive pests in North and North East India is very recently found to be causing wide spread damage in the banana growing tracts of Ernakulam and Trissur districts of Kerala. The present investigation was envisaged to properly understand about the nature of attack, symptomatology, bio-ecology, morphology and the preliminary control measures of the pest species under both field and laboratory conditions. The insect pest is associated with the banana plants throughout the year in Kerala in overlapping generations with its maximum population during both the monsoon periods. This insect has a very congenial condition in Kerala for their survival and multiplication in general and its hot spots of infestation were identified to be around Alwaye-Perumbavoor regions in Ernakulam District. Of late the infestation was observed to be spreading to other Districts also. The banana varieties more susceptible to its attack were found to be Nendran, Palayankodan and Poovan while; Njalipoovan was relatively tolerant. The adult weevils preferred to oviposit on the outersheaths on 3-4 months old plants coinciding with the peduncle formation at a height ranging from 3-4 meter above ground level. The weevil grubs bored into the pseudostem portions and cause extensive tunnelling and riddling leading to weakening of growth, delayed flower emergence, smalling of bunches and finally breakage and lodging leading to partial or complete loss of the crop. The biology, morphology and biomorphometrics of the insect under laboratory conditions were worked out in detail. Because of the peculiar nature of the plant and the fruit produce, as well as the type and nature of the pest species, chemical means of control by spray impregnation of natural products, injection of systemic insecticide through root, rhizome and pseudostem portions and padding technique with fumigant insecticide gave inconclusive results. Bio-control with the parasitic nematode, DD-136, Steinernema sp. eventhough showed good in vitro mortality under lab conditions, it was not successful under field condition. From the above studies, it was found that, to contain the pseudostem weevil infestation effectively, an integrated pest management strategy with special emphasis on cultural techniques on a community basis should be evolved and practiced.
Open Access
Host resistance in cowpea ( Vigna unguiculata (L .) Walp) to the pod borer Maruca testulalis (Geyer) (PyralidaeiLepidoptera)
(Department of Agricultural Entomology , College of Horticulture, Vellanikkara, 1992) Anitha Kumari, V; KAU; Sheila, M K
An investigation on the host resistance in cowpea ( Vigna unguiculata (L.) Walp) to the pod borer Maruca testulalis (Geyer) was carried out by screening 100 varieties of cowpea during 1990 - 91. These were classified into highly susceptible, moderately susceptible and moderately resistant classes. This study rules out the chance of any of the varieties screened to be resistant to this particular pest. Selected accessions from the three different classes based on the field evaluation, were subjected to artificial infestation by the first instar larvae of M. testulalis on caged plants in the green house. Here too, the susceptibility spectrum was found to be similar to the trend observed in the field trial. The accession V30 was identified to be the most moderately resistant type and V100 as the most susceptible one. In the studies on antibiosis it was found that the larvae reared on moderately resistant type took longer durations of development as compared to the susceptible ones. The larval survival as well- as the adult emergence was lower in the resistant types The highly susceptible accessions produced more females than the resistant lines. The fecundity of F females was adversely affected when the larvae were reared on the moderately resistant accessions. Among the biophysical components, though the pod wall thickness and pubescence of the pods did not show any correlation with the level of borer infestation, the length of flower stalks, disposition of corolla, calyx and seeds and the nature of seed testa, had a positive influence on its distribution. Positive correlations were also detected between the mean percentage of total sugars, crude protein, amino acids and nitrogen in the pods on the one hand and pod damage on the other.
Open Access
Relative susceptibility of populations of Amrasca biguttula biguttula (ISHIDA) infesting Bittergourd (memordica charantia L.) collected from different locations to insecticides part II
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 1994) Jyothi, Bindu P; KAU; Sosamma, Jacob
A study was undertaken at the college of Horticulture, Vellanikkara during 1993-94 to evaluate the relative susceptibility of eight different populations of Amrasca biguttula biguttula (Ishida) on bittergourd collected from four districts of Kerala state to six insecticides belonging to different chemical groups. Two different localities were selected for the collection of the leaf hopper, from each district. The selected localities were, Pattikadu and Nedupuzha (Thrissur district), Pothappara and Odanallur (Palakkad district), Wandoor and Chattipparambu (Malappuram district) and Vempalli and Kurichi (Kottayam district). All the populations were collected from farmers fields which were subjected to regular insecticidal spraying. The insecticides selected for the study belong to different chemical groups viz. organophosphorus compounds (quinalphos, monocrotophos and phosphamidon), organochlorine compounds (endosulfan), synthetic pyrethroid (deltamethrin) and CHO compound (ethofenporx). Among these insecticides, the organophosphorus compounds were widely used by the farmers for controlling this pest in the field. Relative toxicity of different insecticides to different populations were found by leaf dipping technique of bioassay and the results were subjected to probit analysis (Finney, 1971). Based on the relative toxicity studies it was clear that endosulfan was the most toxic insecticide against A.biguttula biguttula collected from all the eight localities. Monocrotophos ranked second in toxicity against populations from Thrissur district while deltamethrin was proved to be the second highly toxic insecticide to Palakkad and Kottayam hopper populations. Against Malappuram populations of A.biguttula biguttula highest toxicity of endosulfan was followed by ethofenprox. Phosphamidon was found to be relatively less toxic to this pest. Quinalphos, the commonly used organophosphorus insecticide was found to have least toxicity and thereby it was observed to be ineffective in controlling this pest in bitttergourd in all the four districts. Great variation was observed in the relative toxicity values of different insecticides indicating their difference in toxicity level to A. biguttula biguttula. The order of toxicity of different insecticides was found to be the same between the two populations from each district but varied with populations from different districts. Organophosphorus compounds were found to be relatively less toxic than endosulfan, deltamethrin and ethofenprox belonging to other groups. Therefore, the use of quinalphos against A.biguttula biguttula among the farmers has to be discouraged and endosulfan can be advocated against A. biguttula biguttula in bitterfourd as an alternative. Carbaryl was proved to be ineffective against leaf hopper populations in bittergourd earlier (Sabitha, 1992). The relative susceptibility studies with populations of A. biguttula biguttula from the four districts revealed that all the eight populations were highly susceptible to endosulfan. The LC50 value of endosulfan was found to be very low, ranging from 0.00022 to 0.00041 per cent. At the same time all the populations were least susceptible to the most commonly used organophosphorus insecticide quinalphos. All the populations showed higher susceptibility to endosulfan, deltamethrin and ethofenprox than the organophosphorus insecticides. Thrissur population was more susceptible to monocrotophos next to endosulfan. Palakkad and Kottayam populations were more susceptible to deltamethrin while Malappuram populations indicated more susceptibility to ethofenprox, next to endosulfan. The LC50 value of phosphamidon ranged from 0.02 to 0.06 and all the eight populations of A.biguttula biguttula manifested lower susceptibility to this insecticide in comparison with the other chemicals
Open Access
Management of pests of amaranthus and bhindi using plant extracts
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 1990) Srinath, B; KAU; Sasidharan Pillai, K
Water extracts of eight locally available plants of known insect control potential were screened at 2 and 4 per cent concentrations against pests of amaranthus and bhindi in a pot culture experiment in comparison with carbaryl and tobacco decoction. T. nerifolia followed by A. indica, C. infortunatum and E. odoratum were highly effective against P. basalis on amaranthus and A. gossypii on bhindi. C. infortunatum and T. nerifolia followed by A. indica, N. oleander and E. odoratum were effective against A. biquttula biguttula. T. nerifolia and A. indica followed C. infortunatum and E. odoratum reduced damage caused by E. vittella. Carbaryl 0.2 per cent was superior to plant extracts and tobacco decotion was effective only against aphids. A laboratory study was undertaken for augmenting the toxicity of five aqueous plant extracts by adding with teepol, soap and coconut oil at varying concentrations and combinations. Toxicity of eight and four per cent extracts of C. infortunatum and eight per cent extract of T. nerifolia with teepol, coconut oil and soap reduced the adult emergence of S. litura. A. indica and T. nerifolia were more effective against A. gossypii when the extracts were mixed with soapwater. Teepol and coconut oil also had the same effect with eight per cent T. nerifolia. Field experiment was conducted with the extracts of A. indica, T. nerifolia and C. infortunatum at two and four per cent concentrations without and with soap against pests of amaranthus and bhindi using carbaryl and tobacco decoction as standards. Carbaryl was superior to plant extracts in controlling the population of pests. Four per cent extracts of A. indica, two and four per cent extracts of T. nerifolia and C. infortunatum protected amaranthus against A. crenulata and P. basalis. Toxicity of the extracts A. indica and T. nerifolia was augmented with soap at lower concentration. All the plant extracts increased the crop yield but lesser then carbaryl. Tobaco decoctin failed to control the pests incidence and to increase the yield. Two and four per cent extracts of T. nerifolia caused heavy mortality of A. gossypii. Four per cent extract of A. indica was more effective than carbaryl followed by C. infortunatum, and T. nerifolia against A. crenulata on bhindi. C. infortunatum with soap was efficient against A. biguttula biguttula. Four per cent extracts of T. nerifolia and A. indica were highly effective against E. vitella. T. nerifolia four per cent was effective against S. derogate. Plant extracts were not toxic as carbaryl to C. sexmaculata. All the plant extracts other than at 2 per cent concentration increased the yield and T. nerifolia recorded maximum, but lesser than carbaryl. Tobacco decoctin had no impact on yield. Toxicity of 2 per cent extract of T. nerifolia was augmented with soap against pests of bhindi.

Kerala Agricultural University, Thrissur

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