Growth, development and reproduction of Dianphania india on different cucurbitaceous plant varieties
Abstract:
[Aim]
To compare the growth, development and reproduction of the
cucumber moth, Dianphania india, an important pest of cucurbitaceous
plants, on seven, different, cucurbitaceous plants (cucumber, pumpkin,
watermelon, bitter gourd, melon, sponge gourd and winter melon). [Methods] Larval feeding and adult oviposition
preferences for each of the seven cucurbitaceous plants were determined using
the covering method and the leaf dish methods, respectively and the effects of
feeding on different plants on the growth, development and reproduction were
measured and compared. [Results] After
6 and 12 hours, the number of 2nd instar larvae was highest on pumpkin [6 h: (5.60
± 3.85) ind.; 12 h: (7.20 ± 2.39) ind.], followed by cucumber [6 h: (5.20
± 0.80) ind.; 12 h: (3.40 ± 0.51) ind.], and lowest on winter melon [6 h: (0.40
± 0.40 ind.; 12 h: (1.20 ± 0.37) ind.]. After 6 h, the number of 4th
instar larvae was highest on pumpkin [(5.0 ± 1.0) ind.], but there was no
significant difference in the number of larvae on pumpkin [(4.8 ± 0.58) ind.] and
cucumber [(4.8 ± 0.37) ind.] after 12 h , which was significantly higher than
that on other hosts (P<0.05). Adults laid the most eggs [(325.5 ± 28.51) grains] on
cucumber, and the least [(92.67 ± 24.58) grains] on winter melon. The duration
of the entire larval stage on different hosts can be ranked as follows: Winter
melon > watermelon > melon > bitter gourd > sponge gourd >
pumpkin > cucumber. Pupae of larvae that had fed on cucumbers and pumpkins
were the longest [(1.20 ± 0.045) cm, (1.20 ± 0.011) cm, respectively), whereas
those of larvae that had fed on melon and cucumber were the heaviest[ (0.054 ±
0.003 2) g]. The effect of host plant on the duration of the pupal period can
be ranked as follows: Bitter gourd > melon > watermelon > winter
melon > sponge gourd = pumpkin > cucumber. The duration of the adult
preoviposition period on different host plants can be ranked as follows: Melon
> watermelon > bitter gourd = winter melon > sponge gourd > pumpkin
> cucumber. Female moths that had fed on cucumber laid significantly (P <
0.001) more eggs [(340.00 ± 28.51) grains], than those that fed on the other
plants. Moreover, both male and female moths that had on cucumbers had the
longest life span [(25.4 ± 0.54) and (24.3 ± 0.54) d]. [Conclusion] Although cucumber moths can grow, pupate
and oviposit normally on each of the seven cucurbitaceous plants tested,
cucumber is the most suitable host plant for this species. Although larvae have
an initial preference for pumpkin, females prefer to lay eggs on cucumber
leaves.