Effect of host-plant species on the survival, adult longevity and fertility of predatory bug, macrolophus caliginosus wagner [hemiptera : miridae]

Abstract EN

Two laboratory experiments were carried out under controlled conditions.

First exp periment was to study the development and survival of nymphs of Macrolophus caligin nosus Wagner, when offered clean leaf-discs of tobacco, eggplant, tomato, pepper or Pelargonium peltatium only.

The second experiment was to study the adult longevity and fertility of M.

caliginous offered greenhouse whitefly Trialeurodes vaporariorum (Westwood) (GHWF), on different host-plant.

Although newly hatched M.

caliginous nymphs did not survive on plant sap alone, adults could live and even produce offspring.

However, when M.

caliginous offered these plants as ovipositor sites and fed on T.

vaporariorum infestation, the intrinsic rate of increase of M.

caliginous was the higher est on tomato, followed by Pelargonium, eggplant, tobacco and pepper.

M.

caliginous sus showed a potential for reproduction on tomato and eggplant, and might be able to double its population in 15.6 days on tomato and 72.8 days on eggplant.

However, M.

caliginous would be unable to establish a satisfactory population on either tobacco or pepper as its life table calculations showed that doubling time was 575.2 days on tobacco co and - 90.4 days on pepper.

Thus, it can be concluded that inter-cropping of tobacco, pepper and eggplant with Pelargonium might enable M.

caliginous to increases its “fertility” to build up population sufficiently to suppress T.

vaporariorum infestations in a shorter time than in the absence of Pelargonium.

Furthermore, M.

caliginous females preferred to lay their eggs in solanaceous plants rather than in Pelargonium when both plants were offered together, although there was no significant effect of the host-plant species on the incubation period.