The effect of three green gram cultivars (PDM 54, PUSA BAISAKHI and SAMRAT) on the biology of Spilosoma obliqua Walker (Lepidoptera: Arctiidae) was studied using age-stage, two-sex life table. We also studied food utilization efficiency measures of larvae on green gram cultivars. The nutritional and antinutritional factors of leaves of green gram cultivars were determined. The preadult development time of S. obliqua was shortest on PDM 54 (35.54 days) and longest on SAMRAT (39.29 days). The fecundity was highest on PDM 54 (318.32) and lowest on SAMRAT (250.20). The net reproductive rate (R0) ranged from 37.53 on SAMRAT to 79.58 on PDM 54. The intrinsic rate of increase (r) was higher on PDM 54 (0.1148 day−1) and PUSA BAISAKHI (0.1018 day−1) than SAMRAT (0.0875 day−1). The finite rate of increase (λ) was lowest on SAMRAT (1.0915 day−1). Mean generation time (T) was shortest on PDM 54 (38.12 days) and longest on SAMRAT (41.42 days). Population projection revealed that the population growth was slowest on SAMRAT. The growth rate of sixth instar larvae was highest on PDM 54 and lowest on SAMRAT. The lower level of nutritional factors such as total carbohydrates, proteins, lipids, amino acids and nitrogen content, and a higher level of antinutritional factors such as total phenols, flavonols and tannins influenced higher development time and lower fecundity of S. obliqua on SAMRAT than other cultivars. These findings suggested that SAMRAT is a less suitable cultivar to S. obliqua than other cultivars, and this cultivar can be promoted for cultivation.

BACKGROUND: The viviparous aphid Aphis craccivora Koch (Hemiptera: Aphididae) is a serious threat to the crop yield of Lathyrus sativus L. (Fabaceae), commonly known as grass pea. The synthetic insecticides applied to control this insect pest are not safe for the environment. Hence, it is necessary to find volatile organic compounds (VOCs) from two cultivars [BIO L 212 Ratan (BIO) and Nirmal B-1 (NIR)] of L. sativus plants causing behavioral preference of A. craccivora. RESULTS: The VOCs from undamaged (UD), insect-damaged (ID) [plants on which 50 or 100 adults of A. craccivora were fed for 4 h (ID 50 or ID 100)], and mechanically damaged (MD) plants were identified and quantified by gas chromatography-mass spectrometry and gas chromatography-flame ionization detection analyses, respectively. Total VOCs were higher in ID plants compared to UD plants of each cultivar. However, total VOCs were higher in NIR cultivar compared to BIO cultivar for both UD and ID plants. Benzyl alcohol was predominant in volatile extracts of all treatments. In Y-tube olfactometer bioassays, females showed preference towards volatile extracts of UD, ID, and MD plants of each cultivar compared to the control solvent (CH 2 Cl 2). Insects preferred certain synthetic blends comparable to volatile extracts of UD, ID, and MD plants of each L. sativus cultivar against the control solvent. CONCLUSION: Females preferred a synthetic blend of benzyl alcohol, 1,3-diethylbenzene, thymol, and 1-hexadecene at ratios of 142.49: 62.03:1.18:1 dissolved in 25 ∼L of CH 2 Cl 2 in olfactometer bioassays, which could be used in developing lures to control this insect pest.

Green gram, Vigna radiata (L.) Wilczek, is an important pulse crop of Asia. Severe attack by the larvae of Spilosoma obliqua Walker (Lepidoptera: Arctiidae) causes defoliation of green gram and reduces seed yield. Females lay eggs on the leaf surface, and therefore, surface wax plays an important role as short‐range attractant and oviposition stimulant. So, we have attempted to find out whether leaf surface wax compounds (alkanes and free fatty acids) from three green gram cultivars (PDM 54, PUSA BAISAKHI and SAMRAT) could act as short‐range attractant and oviposition stimulant in females. The TLC, GC‐MS and GC‐FID analyses of n‐hexane extracts revealed 20 n‐alkanes from n‐C15 to n‐C36 and 13 free fatty acids from C12:0 to C21:0, whilst linoleic acid was unique in SAMRAT. Pentacosane was the predominant amongst n‐alkanes in the leaf surface waxes of three cultivars. Heneicosanoic acid and palmitoleic acid were the predominant free fatty acids in the leaf surface waxes of PDM 54, and PUSA BAISAKHI and SAMRAT, respectively. Females were attracted towards one leaf equivalent surface wax of three green gram cultivars against solvent controls (n‐hexane) in Y‐tube olfactometer bioassays. A synthetic blend of pentacosane, heptacosane, nonacosane, hexatriacontane, palmitoleic acid, linolenic acid and stearic acid, a synthetic blend of pentacosane, hexatriacontane and stearic acid, and a synthetic blend of hexatriacontane, linolenic acid and stearic acid resembling in amounts present in one leaf equivalent surface wax of PDM 54, PUSA BAISAKHI and SAMRAT, respectively, served as short‐range attractant and oviposition stimulant in females. Females showed equal preference for egg laying towards the above three synthetic blends when these blends were tested against each other, and hence, these blends could be employed in development of baited traps in pest management strategies.

Diaphania indica (Saunders) (Lepidoptera: Crambidae) is an important phytophagous pest of Trichosanthes anguina L. in India. We studied life table parameters by age-stage, two-sex, amylolytic and proteolytic activities, and food utilization parameters of D. indica on the leaves of three T. anguina cultivars (Baruipur Long, Polo No. 1 and MNSR-1). Further, nutrients (total carbohydrates, proteins, lipids, amino acids and nitrogen) and antinutrients (total phenols, flavonols and tannins) in leaves were determined. The development time (egg to adult emergence) was the shortest on MNSR-1 (19.79 d) and the longest on Polo No. 1 (25.72 d). Fecundity was the highest and lowest on MNSR-1 (259 eggs) and Polo No. 1 (151.22 eggs), respectively. The lowest intrinsic rate of increase (rm) and net reproductive rate (R0) of D. indica on Polo No. 1 were 0.1112 d−1 and 27.22 offspring individual−1, respectively. The mean generation time (T) was the shortest on MNSR-1 (23.99 days) and the longest on Polo No. 1 (29.70 d). The larvae of D. indica fed with MNSR-1 had the highest level of amylolytic and proteolytic activities, and the lowest activities were in the larvae fed with Polo No. 1. The fifth-instar larvae fed with Polo No. 1 had the lowest consumption index and growth rate. The higher larval development time and lower fecundity of D. indica on Polo No. 1 were due to the lower level of nutrients and a higher level of antinutrients than other cultivars. Our results concluded that Polo No. 1 cultivar could be suggested for cultivation.

Aphis craccivora Koch (Hemiptera: Aphididae) is an important pest of Lathyrus sativus L. plants, and causes retarded plant growth and loss of seed production. The insect sucks cell sap from flowers and lays nymphs on flowers. Hence, an attempt has been made to observe whether flower surface wax compounds (alkanes and free fatty acids) from two cultivars (BIO L 212 Ratan and Nirmal B-1) of L. sativus could act as short-range attractant and stimulant for nymph laying by adult viviparous females. The n-hexane extracts of flower surface waxes were analyzed by TLC, GC-MS and GC-FID analyses. Twenty one and 22 n-alkanes between n-C12 and n-C36 were detected in BIO L 212 Ratan and Nirmal B-1, respectively; whereas 12 free fatty acids between C12:0 and C22:0 were identified in both cultivars. Pentadecane and tridecanoic acid were predominant n-alkane and free fatty acid, respectively. One flower equivalent surface wax of both cultivars served as short-range attractant and stimulant for nymph laying through Y-tube choice experiments and I-tube viviparity assays, respectively, by adult viviparous females. A synthetic blend of nonacosane, tridecanoic acid and linoleic acid, and a synthetic blend of tetradecane, pentadecane, nonacosane, tridecanoic acid and linoleic acid resembling in amounts as present in one flower equivalent surface wax of BIO L 212 Ratan and Nirmal B-1, respectively, served as short-range attractant and stimulant for nymph laying by adult viviparous females. This study suggests that both these blends could be used in lures in the development of baited traps in pest management programmes.

Two Commelinaceae weeds, Commelina benghalensis L. and Murdannia nudiflora (L.) Brenan, are abundant in rice fields of India. Larvae and adults of Lema praeusta (Fab.) (Coleoptera: Chrysomelidae) voraciously consume these two weeds. Synthetic herbicides are applied to control both weeds, but applications of these substances have harmful effects in environment and beneficial organisms. So, it is necessary to use native biocontrol agent to control these weeds. Hence, an attempt has been made to find volatile organic compounds (VOCs) from both weeds causing attraction of L. praeusta. Behavioural responses of L. praeusta towards volatile blends from undamaged (UD), insect‐damaged (ID: plants after 6 or 48 hr of continuous insect feeding) and mechanically damaged (MD) plants were conducted by Y‐tube olfactometer bioassays. Benzyl alcohol was predominant in VOCs of UD plants and M. nudiflora after 48 hr of insect feeding. Benzyl alcohol and cuminaldehyde were both predominant in VOCs of C. benghalensis after 48 hr of insect feeding. Females were more attracted towards volatile blends from plants after 48 hr of insect feeding compared to undamaged plants. Females showed attraction towards a synthetic blend of seven compounds—7.28 µg (Z)‐3‐hexen‐1‐ol, 0.93 µg trans‐isolimonene, 19.18 µg benzyl alcohol, 0.16 µg undecane, 1.07 µg 1‐nonanol, 1.23 µg 1‐undecanol and 0.47 µg 1‐eicosene resembling the amounts released by C. benghalensis after 48 hr of insect feeding during 1 hr or a synthetic blend of six compounds—18.10 µg benzyl alcohol, 0.25 µg undecane, 0.56 µg 1‐nonanol, 1.37 µg 1‐undecanol, 0.35 µg 1‐eicosene and 2.19 µg phytol resembling the amounts released by M. nudiflora after 48 hr of insect feeding during 1 hr. This study concludes that both blends could be used to attract the biocontrol agent during early vegetative period of these two weeds, which could lead to eradication of weeds from rice fields.

Larvae of Spilosoma obliqua Walker (Lepidoptera: Arctiidae) feed on the leaves and owers of green gram [Vigna radiata (L.) Wilczek] and reduce seed yield. Therefore, it is interesting to observe whether undamaged (UD) and insect-damaged (ID, plants after feeding by S. obliqua larvae) plants cause attraction of conspeci c adult moths. Females showed attraction towards volatile blends of UD, ID and mechanically-damaged (MD) plants of three green gram cultivars [PDM 54 (PDM), Pusa Baisakhi (PUSA) and Samrat (SAM)] in Y-tube olfactometer bioassays. Females were more attracted towards volatile blends of ID plants of a particular cultivar than UD plants of the same cultivar. Total amount of volatiles was higher in ID plants than UD plants. Some herbivore-induced plant volatiles − 3Z-hexenal, 1-hexanol, 3Z-hexenyl acetate, 2-octanol and ocimene were attractive to the insect. Females were attracted towards three synthetic blends (µg in 25 µl CH 2 Cl 2 ) comprised − 2.

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