Relative susceptibility of certain recommended maize cultivars to infestation by Sesamia cretica Led. and Ostrinia nubilalis Hub. in relation to the sowing date

الملخص EN

The present study was conducted in Experimental Farm, Faculty of Agriculture, Moshtohor, Qaliubiya Governorate, Egypt to evaluate the susceptibility of thirteen of maize cultivars against the natural infestation by Sesamia cretica Led and Ostrinia nubilalis Hub.

during 2014 and 2015 seasons.

The experiment was designed at randomized complete blocks (R.C.B.D).

Moreover, the influences of two sowing dates (May and June 20th) were also tested.

The highest perforated leaves and dead heart rates were recorded for SC30N11 cultivar (8.0%, 7.4%) and (2.5%, 1.7%) for the two seasons, respectively.

While, TWC Maged 7 cultivar recorded the least infestation rate showed (2.7%, 2.0%) and (0.7%, 0.7%) for both seasons, respectively.

On the other hand, the remaining maize cultivars showed moderate infestation rates by S.

cretica.

As for O.

nubilalis infestation, SC30b74 cultivar showed the highest mean number of holes / 10 plants (18.67 and 22.67) for two seasons of study, respectively.

On the contrary, SC 3062 cultivar was the highest resistant one among all the tested maize cultivars where the recorded mean numbers of holes were (2.67 and 6.33) during two successive seasons, respectively.

As for the relationship between the sowing date and infestation, maize plants were sown on May 20th received the least infestation rate by S.

cretica while, those were sown on June 20th harbored the highest infestation.

Also, plants were sown in May (recommended date) received the lowest number of larvae and subsequent holes of O.

nubilalis.

The determination of the susceptibility or resistance rates in the different varieties is an essential prerequisite to the maize breeder seeking the development of varieties that could resist or tolerate S .cretica or O.

nubilalis infestations.