ISHS Acta Horticulturae 574: VII International Symposium on Vaccinium Culture
DIAGNOSIS AND DESCRIPTION OF WIDESPREAD SURFACTANT INJURY ON BLUEBERRIES IN NORTH CAROLINA |
| Authors: | W.O. Cline, P.V. Oudemans |
| Keywords: | Phytotoxicity, Vaccinium corymbosum, adjuvant, abiotic, mummy berry |
| Abstract:
In April of 1999, growers in southeastern North Carolina began reporting leaf and flower blighting on cultivars susceptible to mummy berry caused by Monilinia vaccinii-corymbosi. Examination revealed that symptoms were due to spray injury rather than to the mummy berry disease. Dessication of new shoots, burned blossoms and scarred fruit were observed by sixteen growers on over 1,000 acres (404 ha). A combination of surfactant (Cohere) and two fungicides (Benlate + Indar) had been applied to affected fields. Air blast, aerial or boom-type sprayers were used, and symptoms varied with sprayer type and concentration of the spray solution. Damage was most severe where air blast sprayers were used. Air blast applications are typically made by traveling down every third or fourth row middle, and bushes on rows closest to spray middles were significantly more affected. One field of the early-blooming cultivar O’Neal averaged 42.5 percent yield loss, but losses ranged from 8 to 84 percent in this field depending on proximity to the spray middle. Replicated trials in North Carolina and New Jersey showed that the injury was due solely to the surfactant. Variations in severity were attributable to application method, rate, cultivar and crop phenology. | |
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