CROPS NOT SO GOOD

Press, Volume CV, Issue 31001, 5 March 1966, Page 8

CROPS NOT SO GOOD

fLANTERBURY farmers in , general have been fortunate in having a very good harvest thi s season and wheat yields have generally been at very high levels. It is almost inevitable, however, that some areas should not 1 be so favoured and one of 'these areas is the HawardenWaikari district where the i ; local chairman of Federated 'Farmers, Mr J. H. A. Hollis, 'said recently that the general ' consensus of opinion in the district was that the harvest I had not been as good as in the I past—that in fact they had had a below average harvest. From comments of district i ."armers it seems that the area I has had to put up with a numi her of natural visitations quite apart from disease problems. There was a frost about Christchurch show time and then another in December I which caught barley and later i flowering crops. There was ialso some hail and an odd dry spell of weather, in what has i generally been a fairly wet season, did not help matters. From a disease point of view barley yellow dwarf .virus has been a yield reducing factor in particularly the : early sown wheat crops and ,one farmer in the district commented that early sown [crops that might have been 'expected to yield 65 to 70 I bushels to the acre had only ; gone 35 to 45 bushels to the |aire. ! There is a feeling that jwhere crops were sown early this season—and some farmers are forced to begin sowing early to get large areas of wheat in—crops would have benefitted quite markedly from an early spraying against aphides in May where they were well up by the beginning of June. There is some feeling that aphis traps in the district might have given a guide to the presence I of aphides at this time and could have led to farmers be-

ing advised on this issue. 1 On one property a few rounds of a crop near an old water dam were sprayed in late June and when it came to harvesting this crop it was found that the area sprayed yielded about twice as well as the unsprayed area of the paddock. The opinion was expressed recently that spraying of such crops might well be a sound insurance in any season and that some crops might have to be sprayed twice in a season to give complete control. Asked to comment on this situation Dr. R. C. Close, a plant pathologist of the Plant Diseases Division of the Department of Scientific and Industrial Research, said this week that barley yellow dwarf virus had been prevalent in this area. A number of crops (sampled by officers of the Department of Scientific and Industrial Research had been found to be infested with aphides in June. In a trial laid down by the Department of Agriculture in the Waikari area there had been a good response with an increased yield to spraying in early September. This crop had been sown at the end of May and when first inspected at the end of June had become infested with aphides. These had remained in the crop and had built up in. the spring and infested a large proportion of the unsprayed part of the crop with barley yellow dwarf virus. Again where a crop in the same district had been sown in April it had been found to be heavily infested with aphides when first inspected at the end of June—almost every plant then had aphides on it The Department of Agriculture had also laid down a spray trial in this crop in early September, but there had only been a small re-

'sponse lo spraying. In this case Dr. Close said that a spray in May might have been worthwhile in preventing the primary build-up of aphides and infection with yellow dwarf virus. Dr. Close said that a possibility was the use of gran- ' tiles at sowing to control aphis infestation in early autumnsown crops in the danger period from May through to June. On the question of trapping | aphides Dr. Close raid it was I a guide to the presence or I absence of aphides in an area, ! but the actual sampling of a i crop and inspection of plants 'was a more reliable method lof determining whether there (was an aphis infestation in ian individual farmer’s area. (There was a limit to the number of traps that could Ibe serviced by the Depart[ment of Scientific and Industtrial Research at Lincoln.