دراسة أولية عن العلاقة بين خلط الأصناف في الذرة الشامية و قابليتها للإصابة بحشرة حفار ساق الذرة Sesamia cretica Led. (Lepidoptera : Noctuidae)‎

الملخص EN

The relationship between the use of corn cultivar mix¬tures and its susceptibility to infestation with the corn stem borer (Sesamia cretica Led., Noctuidae, Lepidoptera) was studied.

Experiments were conducted in the Experimental Farm of the Faculty of Agriculture, Abu Ghraib, Iraq, by planting mixtures of the corn cvs.

«XL», «DC» and «501», during the spring and fall seasons of 1988.

Results showed that mixing cultivars affected the level of infestation with the corn stem borer.

When the susceptible cultivar «NeIum» was planted as a mixture with other cultivars with different genetic backgrounds, infestation with the insect was reduced.

In addition, the number of larvae per plant, % of injured leaves and number of holes per stem were reduced which led to an increase in yield of the same culti- var as compared to when planted as pure (non-mixed) culti¬var.

It was also observed that the infestation of the tolerant cultivar «Dewania» was increased when planted as a mix¬ture during the spring season, whereas no significant differ¬ence was observed when the same cultivar was planted mixed with other cultivars during the fall growing season.

There was a significant different cultivars tested when planted singly.

Infestation levels of the cvs.

«DC» and «501» were high, whereas that of the cvs.

«Nelum» and «Dewania» was less during both growing seasons.

There was a negative correlation between insect infestation and plant height of the different cultivars tested.