K. Selvaraj

Biochemical effects of cultivated and wild jute species on life stages of the broad mite, Polyphagotarsonemus latus (Prostigmata: Tarsonemidae)

Abstract We studied the life cycle of the broad mite, Polyphagotarsonemus latus (Banks) (Prostigmata: Tarsonemidae), on 2 cultivated jute species (Corchorus olitorius L. and Corchorus capsularis L.; Malvales: Malvaceae) and 5 wild species (Corchorus aestuans L., Corchorus pseudo-olitorius Islam & Zaid, Corchorus fascicularis Lamarck, Corchorus tridens L., and Corchorus trilocularis L.) under laboratory conditions. Results showed that the egg incubation period, larval and nymphal durations, and adult male and female longevities of P. latus varied significantly on different jute species. The larval period (mean ± SD) was significantly shorter (57.00 ± 2.07 h) on C. olitorius than on C. fascicularis, C. aestuans, and C. tridens (68.00 ± 1.58 to 72.00 ± 1.30 h). The phenol content was greatest in C. trilocularis (61.92 ± 1.91 μg/g), and it was 16.26 ± 1.34 μg/g and 20.45 ± 1.43 μg/g in C. olitorius and C. capsularis, respectively. The polyphenol oxidase content was smallest in C. capsularis (0.99 ± 0.10 μg/mL) as compared with 2.38 ± 0.15 μg/mL in C. fascicularis. The protein content in the wild species was significantly less than in the cultivated species. In the wild species, the peroxidase content varied from 3.93 ± 0.17 to 7.08 ± 0.16 μg/mL, and it was 3.23 ± 0.12 to 3.70 ± 0.14 μg/mL in the cultivated species. The leaf biochemical constituents of jute species were correlated with mite life stages and incidence. The larval period and adult female longevity had significantly negative correlations with polyphenol oxidase content and positive correlations with protein content. The greatest mite population was observed on C. olitorius, and the smallest mite population was observed on C. trilocularis, at 50 d after sowing. The mite populations increased on all the jute species except C. trilocularis at 50 d after sowing. Based on the duration of life stages, the present study showed that among the 7 species of jute, the cultivated C. olitorius was the most suitable host for broad mites. It is evident that biochemical leaf constituents have an important role in the growth and buildup of mite pests in these crops. On the basis of the relative resistance and susceptibility of the jute species, appropriate interspecific crosses may provide a platform for developing resistant varieties for broad mite management.