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SOME PHYSIOLOGICAL CHARACTERISTICS AND THE AGRONOMIC IMPORTANCE OF DIPTERA DAMAGE TO GRASSES |
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| Authors: | Tibor I Emecz |
| Institution: | Welsh Plant Breeding Station, Aberystwyth |
| Abstract: | Shoot-fly larvae cause considerable damage to cultivated grasses; it is greatest when overwintering tillers are lost, resulting in delayed emergence, decreased number of flowering heads and reduced yield of dry matter. An increase in the number of tillers, which often follows the damage, cannot counter-balance the losses because the new tillers are smaller. Different varieties within species, and different genotypes within varieties, show varying degrees of susceptibility to damage, and of capacity to recover from it. Favourable growing conditions promote recovery and reduce losses. Non-cultivated grasses and unploughed leys are sources of infection, not only to cereals but also to cultivated grasses, and it is advisable not to put single plants or seed areas adjacent to old swards. The glasshouse is a special source of infection as it provides conditions favourable for the flies to produce extra generations at unusual times. The importance of further investigations and the development of more economical protective techniques is stressed. |
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