Herbicidal agents as possible aids for roguing diseased seed-potato plants

Summary

Several herbicidal materials were screened as possible roguing agents on potato plants. Most of the materials were rejected because of their slow killing action and failure to prevent regrowth from seed pieces. In greenhouse and field trials, Diesel oil plus 0.4 per cent triethanolamine salt of 2, 4, 5-trichlorophenoxyacetic acid, Diesel oil plus 30 per cent of an Isopropyl N-(3-chlorophenyl) carbamate emulsion, and Diesel oil plus 1 per cent Dow General Weed Killer were found to be suitable for roguing purposes. In subsequent greenhouse trials, a mixture of Diesel oil and 10 per cent MH 30 killed sprayed plants and inhibited sprouting of seed pieces and harvested tubers. This indicates that further work should be be done on mixtures of Diesel oil and the newer growth-regulating compounds as chemical roguing agents.

Trials by seed potato growers have indicated that transporting roguers, roguing chemicals, and spray equipment with a tractor to locate and spray diseased plants is a quick, efficient roguing method. At present, however, the seed-pieces and tubers under sprayed plants must be dug and destroyed before harvesting. Further research may bring forth an ideal herbicidal mixture which would kill all of the seed pieces and tubers of sprayed plants and thus eliminate the need for digging them. The consensus of interviewed growers was that chemical roguing costs less and is more efficient than hand roguing.

The results of these chemical-roguing investigations show that efficient, inexpensive, roguing materials can be used to replace the tedious, costly, and inefficient hand-roguing methods in current use.