WEED HOSTS AND RELATIVE WEED AND COVER CROP SUSCEPTIBILITY TO ROTYLENCHULUS RENIFORMIS IN THE MISSISSIPPI DELTA

Abstract

The reniform nematode (Rotylenchulus reniformis) causes economic losses in cotton and soybean in the southeastern United States, and has the ability to reproduce on more than 300 plant species. Even when the host crop is protected through the use of nematicides or host plant resistance, the potential exists for other plants present in or near the field to support the reniform nematode population. Because of variations in weed susceptibility, nematode virulence, and environmental factors, determining the host status of weeds to local populations of the nematode is needed to provide management recommendations. To identify the most important weed and cover crop hosts for reniform nematodes in the Mississippi Delta, nematode infection was measured on 53 plant species in greenhouse and field surveys. Subsequent greenhouse and field tests were conducted to confirm the host status of nine of these plants. Sicklepod (Senna obtusifolia), spurred anoda (Anoda cristata), entireleaf morningglory (Ipomoeasp.), and velvetleaf (Abutilon theophrasti) were identified as excellent hosts for reniform nematode in this region, supporting nematode populations equivalent to or greater than those developing on susceptible cotton plants included in the tests. Purple (Cyperus rotundus) and yellow (C. esculentus) nutsedges were poor hosts for reniform nematode, despite all underground plant parts supporting nematode infection. Sicklepod, velvetleaf, and entireleaf morningglory were reported to be important hosts for reniform nematode in tests in Alabama and Georgia indicating that efforts to manage these weeds across a wider geographic region may be needed.