EFFECTS OF TIMINGS OF INOCULATION WITH MYCOSPHAERELLA-PINODES ON YIELD AND SEED INFECTION OF FIELD PEA

Inoculated field experiments were carried out in 1994 and 1995 to stud y the effect of the timing of inoculation with Mycosphaerella pinodes (Berk. & Bloxam) Vestergren on disease development, yield reduction an d seed infection, in three field pea (Pisum sativum L.) cv. Bohatyr, c v. Scorpio and cv. Triumph. The greatest impact of inoculation on all disease and yield parameters was at the 8-10 node stage in 1994, and a t the mid-flowering stage in 1995. The lowest impact of inoculation wa s at the pod swell stage for both years. When inoculated at 8-10 nodes , mid-flowering and pod swell stages, M. pinodes reduced yield by 31, 24 and 19%, respectively, in 1994 and 33, 43 and 30%, respectively, in 1995. The 1000-seed weight was not affected by the timing of inoculat ion; however, all inoculations reduced seed weight in both years. Plan t-to-seed transmission of M. pinodes was affected by the timing of ino culation in 1994, but not in 1995. Results of this study suggest that prevention of early infection by M. pinodes will provide the best econ omic return in a mycosphaerella blight control program on field pea.