RESISTANCE OF WINTER WHEATS TO HESSIAN FLY

Stage of growth at the time of the spring emergence of the Hessian fly appears to account for the differential resistance of varieties of winter wheat at Saanichton, British Columbia. Varieties more advanced in growth appear to be more resistant or freer from infestation than varieties less advanced. There was a positive correlation (r = + 0.84) between the number of days to maturity and infestation, and a negative correlation (r = − 0.63) between the height of the wheat and infestation on April 1, about the time the fly emerges.The varieties of winter wheat grown on the Dominion Experimental Station at Saanichton, B.C. showed culm infestation as follows: (i) Practically free from infestation (0–4%) Dawson's Golden Chaff O. 24, Dawson's Golden Chaff (O.A.C. 61) Kanred × Dawson's Golden Chaff, Kharkov × Dawson's Golden Chaff Imperial Amber, O.A.C. 104, Red Rock and Triplet; (ii) Moderately infested (30–80%) Crail Fife, Forty-fold, Hybrid 128, Hussar, Oro, Yanward, and Yaroslav; (iii) Heavily infested (85–100%) Albit, Golden Sun, Jenkins × Ridit, Kharkov, Marshal Foch, Martin, Ridit, Sun, Victor, White Odessa and Yeoman.Nitrate of soda, superphosphate, and a complete fertilizer broadcast or drilled had no significant effect on Hessian fly damage.