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
Evaluation of multi x bi bivoltine hybrids of silkworm
(1998) Rajeni, Narayanan; KAU; Ranjith, A M
In a study undertaken to evaluate the region and season specific multi x bi and bivoltine hybrids of silkworm Bombyx mori, for commercial exploitation in Kerala, six hybrids of silkworm were reared using K-2 and S-36 mulberry varieties under Vellanikkara condition. The crosses used were PM x NB18, PM X NB4D2 and their reciprocals, NB4D2 x NB18 and its reciprocal and PM as check. The evaluation was carried out based on characters like leaf consumption, larval duration and weight, cocoon and shell weights, shell ratio percentage, average filament length, denier, reelability and renditta. The climatic factors were also correlated with major economic characters of silkworm. The present study confirms the superiority of bivoItine silkworm hybrids like NB4D2 x NBI8 and NB18 x NB4D2 justifying their wide acceptance in states other than Kerala. It is evident that if rearing is done in a systematic way, by strictly adhering to the brushing period in correlation with the seasons and if the use of high quality mulberry varieties is advocated these crosses will yield good returns in Veil ani kkara. Though the various economic parameters reflected a variable trend, ultimately when the average filament length/g cocoon, shell ratio percentage and cocoon weight were considered, the bivoltine hybrids performed superior to the others.
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
Isolation of the bioactive pinciples of thevetia nerlifolia juss.(Apocynaceae) and determination of their biological activities
(Department of Entomology, College of Agriculture, Vellayani, 1996) Hebsi, Bai; KAU; George, Koshy
Fresh and dried leaves and seeds of Thevetia neriifolia were evaluated for their antifeedant activity against Henosepilachna vigintioctopunctata, using acetone, benzene, ethanol, hexane, methanol and water as extractants. Based on the percentage of leaf protection, seed extracts were superior to the leaf extracts. Fresh leaf and dried leaf extracts were on par. Among the solvents, ethanol and methanol gave maximum leaf protection closely followed by water. Based on larval starvation, seed extracts were superior to leaf extracts and fresh leaf extracts were significantly better than dried leaf extracts. Water, methanol and ethanol were on par for extracting plant tissues. Soaking of powered plant material well in solvents for 48 hours and filteration was found as effective as soxhlet method for extracting antifeedant components from leaves and seeds of T. neriifolia. Leaves and seeds of the plant showed conspicuous hormonal/sterilant activity on Dysdercus cingulatus and the response was dose dependent. This was evident in post treatment larval mortality, prolonged preovipositional period, emergence of malformed adults and reduced fecundity. Adult longevity, incubation period and hatching percentage of eggs were not affected. Forty per cent and ten per cent of leaf and seed extracts as well as 20 and 5 per cent extracts of the same came on par in juvenomimetic effect. The results showed that seeds were four times more effective than the leaves in their juvenomimetic effect on D. cingulatus. The length of ovary, number of oocytes per ovariole and size of basal, penultimate and antepenultimate oocytes were significantly lower in seed and leaf extract treated females of D. cingulatus. Closer examination of the data revealed that growth of ovary was delayed rather than suppressed by the plant extracts. Levels of protein, glycogen and lipid contents observed on ovary, fat body and haemolymph of treated and untreated insects from first to fifth day after emergence indicated a delay in vitellogenesis and oocyte development in treated insects. Consequently previposition period was prolonged. The effect observed is similar to the effect of chemosterilants reported on some insects earlier. Results indicated that reduction in fecundity of D. cingulatus may be due to the chemosterilant action of T. neriifolia extracts. Bioassay studies in the laboratory revealed the low contact toxicity of leaf and seed extracts of T. neriifolia to S. litura and H. vigintioctopunctata. Chromatographic isolation of different fractions of ethanol extracts of fresh leaf and seed yielded six bioactive fractions from the leaf and four from the seed. Fractions III and IV were absent in seeds. Fractions IV, V and VI obtained from leaves and V and VI from seeds had far higher activity than the remaining fractions and they were on par in their antifeedant effect and larval starvation on H. vigintioctopunctata. Available active fractions were more concentrated in seeds than in leaves. Laboratory studies showed the safety of leaf and seed extracts of T. neriifolia at field doses to Chrysocharis johnsoni, the most important parasite of H. vigintioctopunctata in Kerala. Toxicological studies in albino mice and rats revealed that 400 mg/kg body weight was the LD50 dose of seed extract of T.neriifolia while doses upto 1000mg/kg body weight of leaf extract was not toxic to the animals. Haematological picture of animals chronically exposed to the extracts showed marginal deviations in the haemoglobin content, RBC count, serum cholesterol, SGOT levels in seed extract treated animals from the permissible safe range. Leaf extract treatment caused deviations in SGOT and serum cholesterol. Vacuolation, cytoplasmic acidophilia and degenerative changes in the liver and heart tissues and inflammation of kidney were observed in animals treated with seed extract. Adverse effects of leaf extract were negligible. Replicated field experiments were conducted for two seasons on bittergourd and amaranthus to evaluate the efficacy of crude extracts of T. neriifolia in controlling their major pests. All the extracts viz., ethanol and water extracts of dried and fresh leaves and seed reduced the pest population and the extent of leaf damage. Seed extract was on par with the insecticide check, carbary 1 (0.15 per cent) in bittergourd and malathion (0.1 per cent) in amaranthus. Fresh leaf extract was on par with the seed extract and was superior to extracts of dried leaf in reducing pest population and increasing yield of both the crops. Water extracts of leaves and seed were found equally good for checking the pest population and increasing yield. On cost benefit basis water extracts were found more advantageous to the farmer. Parasitization of egg masses, grubs and pupae in treated plots were on par with control while they were totally missing in the insecticide treated plots. Extracts of T.neriifolia were thus found to be safe to the non – target organisms too. An overall assessment of the results obtained revealed that water extracts of fresh leaf and seed in appropriate doses can be effectively and safely used for the control of important pests of bittergourd and amaranthus without any health hazards and adverse effect on the non target organisms in the agroecosystem. T. neriifolia can be considered as a plant suited for developing effective plant protection chemicals for replacing undersirable synthetic insecticides, especially in integrated pest control calendar.
Open Access
Evaluation of neem triterpenes as ovipositional and feeding deterrents to the tea mosquito bug, Helopeltis antonii Sign. on cashew
(Department of Agricultural Entomology, College of Horticulture,Vellanikkara, 1995) Angaiah, K; KAU; Sitarama Rao, D
Experiments were conducted at the Department of Entomology, College of Horticulture, Vellanikkara, to ascertain the feasibility of utilizing the commercially available neem products for the management of populations of tea mosquito bug, Helopeltis antonii Sign. On cashew, Anacardium occidentale L. The effects of three neem products in altering the ovipositional behaviour and the feeding behaviour of H. antonii through contact and translaminar effects and the number of feeding punctures as affected by the contact and translaminar effects, were tested in comparison with NKS. Radio labelling of cashew seedlings prior to application of treatments and quantification of feeding based on the quantum of radio activity in the bodies of test insects fed on the treated seedlings was developed as a new technique. The study resulted in the following findings. 1. Godrej Achook at 1.6 and 3.2 per cent doses and Rakshak at all the tested doses significantly reduced the number of egg laying sites. 2. Duration of egg laying was significantly reduced by Godrej Achook and Rakshak at 1.6 and 3.2 per cent doses. 3. Significant reduction in the total number of eggs laid was brought about by Rakshak 1.6 per cent and Godrej Achook at 1.6 and 3.2 per cent doses. 4. Rakshak at all doses and Godrej Achhok at 1.6 and 3.2 per cent doses significantly reduced the nymphal duration. The nymphs failed to reach adult hood. 5. Feeding deterrency through contact action was exhibited by the treatments. Nimbecidine and Godrej Achook at higher doses were better. 6. The number of feeding punctures was influenced by the treatments through translaminar effects. 7. Development of feeding punctures was affected by the treatments through contact action also. Higher doses of Godrej Achook and Nimbecidine were better than the other treatments. In conclusion it can be stated that the commercially available neem products showed a high degree of effectiveness in reducing the feeding and oviposition by H. antonii, eventhough the neem tree is an alternate host of the tea mosquito bug. The neem products can be included as candidates for the management of population of H. antonii on cashew.
Open Access
Bionomics of pareuchaetes pseudoinsulata rego barros (lepidoptera:arctiidae) and its interaction with the siam weed chromolaena odorata king and robinson (asteraceae)
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 1995) Lyla, K R; KAU; Abraham, C C
Studies were undertaken on the biology, morphometrics, feeding habits, factors affecting fecundity and fertility of Pareuchaetes pseudoinsulata King and Robinson (Arctiidae : Lepidoptera) and also the plant response of the weed host Chromolaena odorata L. at the College of Horticulture, Vellanikkara during 1990 – 1993. The morphometrics and morphology of the various immature stages and adults have been described. The total life-cycle of P. pseudoinsulata took a total of 46.75 days and the various developmental stages lasted for 5.5 days in eggs, 21.30 days for larvae (seven instars) 1.5 days for pre-pupa and 10.15 days for pupae at a mean ambient temperature of 28.40 C. In feeding trials to assess the relative preference of tender, mature, semi yellow and yellow leaves of C. odorata, it was found that the I instar larvae showed district preference to tender leaves as compared to mature leaves. The I and II instar larvae did not feed on semi-yellow and yellow leaves and they died of starvation when these types of leaves were offered for feeding. Consumption indices decreased as the age of larvae advanced and thus early instars consuming all the types of leaves recorded high indices. The rate of increase in larval weight gain was higher in later instars (VI and VII). Caterpillars feeding on mature, semi-yellow and yellow leaves showed higher Relative Growth Rate during IV to V stage, but during I to II stage, a high RGR was seen on larvae which fed tender leaves. Yellow. leaf diet for late instar larvae adversely affected their development and adult emergence. Highest fecundity was recorded when the parental sex-ratio of moths was kept at 1:1 level followed by 1:2 ratio and 2:1 in that order. Egg production and viability were significantly higher at 250 C and 75 per cent RH as compared to 300 C and 60 per cent RH. Adult food did not show any influence on fecundity but in respect of improvement of egg viability the treatments were advantageous. Total nitrogen content in leaves was maximum on the sixth day of release of four larvae per cage. Leaf nitrogen showed a declining trend when the larval load per plant was increased from the eighth day of release onwards. Soluble nitrogen content in leaves showed an increasing trend with increase in larval load per plant, but this however failed to reach significant levels. Chlorophyll content in leaves got reduced significantly at increased larval population loads and with passage of time of confinement. The natural enemies of P. pseudoinsulata consisted of avian fauna, spiders and ants and parasitoids. Predatory species of ants recorded in association with the insect included Lioponera sp. Oecophylla smaragdina Fabr. Solenopsis sp.and Monomorium sp. Occasionally NPV infection occurred in the laboratory as well as in field cultures causing substantial mortality. The implications of the various findings in reorienting the biocontrol strategies involving P. pseudoinsulata against C. odorata have been discussed.

Kerala Agricultural University, Thrissur

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