Control of Orobanche crenata and Orobanche aegyptiaca in parsley

Parsley (Petroselinum crispum) is a host of the angiosperm root holoparasites Orobanche crenata and Orobanche aegyptiaca in the Mediterranean region and suffers heavy yield and quality losses. Eight field studies were performed to test the efficacy and selectivity of herbicides on Orobanche control in parsley. Initial experiments showed that the amino acid inhibiting herbicides imazapic and glyphosate did not affect the parsley crop and provided excellent Orobanche control. The efficacy of these herbicides was further tested by single and split post-emergence application at different geographical locations, in spring-summer (warm) and fall-winter (cold) growing seasons and on different Orobanche species. Finally the efficiency of tank mix and alternating application of these herbicides was studied. O. crenata and O. aegyptiaca were. completely controlled by split foliar application of imazapic at 2.5-5.0 g/ha or glyphosate 36-72 g/ha, applied on 5-7 leaf parsley before the first cutting and on the young new growth after each cutting. At the low rates herbicides were parsley-safe, but higher rates caused slight crop damage. Split applications of low rates of the two herbicides as a tank mixture were safe to parsley and achieved effective Ordbanche control. Herbicide mixtures and alternating applications are important in inhibiting or delaying the development of herbicide-resistance in weeds including parasitic plants. The findings of this study propose efficient, selective, low cost and easy to apply herbicides for control of Orobanche in parsley. (C) 2002 Elsevier Science Ltd. All rights reserved.