Chickpea Response to Fungicide Application for the Control of White Mold Disease

S. Halley* and John Lukach

Langdon Research Extension Center-North Dakota State University, Box 310 Hwy 5 E Langdon, North Dakota 58249

*Corresponding author PH: (701) 256-2582, E-mail: shalley@ndsuext.nodak.edu

OBJECTIVES

To determine if efficacy of fungicides Equus, Headline, Penncozeb, and Quadris is different for control of white mold (Sclerotinia sclerotiorum L.) at different timings on chickpea (Cicer arietinum L.).

Introduction

Fungicides are being evaluated for control of Ascochyta blight (Ascochyta rabiei (Passerini) Labrousse) in chickpea (garbanzo beans), a serious disease of chickpea. Little information is available regarding white mold effects on chickpea and possible control by fungicides. This is due in part to the growing region of most of the chickpea acreage, arid regions, and the fact that rotations where white mold can be a problem are not practiced in these regions.

MATERIALS AND METHODS

The cultivar �Myles�, a desi type, was planted notill on a site with extensive cropping history notill. Previous crop was barley. A double disk drill planted 11 rows, 7 rows 6-inch spacing for data collection and two rows each side as border for fungicide drift containment, at 175,000 count pure live seed/acre on 16 May in a notill management system. The 16 ft long plots were arranged in a randomized complete block design arranged as a fungicide by timing factorial. The seed was inoculated with Rhizobium bacteria, 6 oz/1000 ft row. To improve chance of infection sclerotia of Sclerotinia sclerotiorum were hand broadcast and surface covered by harrowing prior to seeding. Roundup Ultra 1.5 pt/acre and Spartan 5.33 oz/acre herbicide were applied in 20 gpa water post plant 17 May. Select and oil, 8 fl oz + 1 qt oil/acre, were applied for weed control on 21 June by backpack sprayer at 14.4 gpa at 40 psi. Hand weeding operations controlled remaining weeds.

Fungicides were applied by CO₂ backpack sprayer at 18 gpa with hydraulic nozzles XR8002 oriented downward from horizontal about four days after first flower on 5 July. Ascospores were sprayed at 8 a.m. on 20 July about three hours before the second fungicide applications. The incidence of white mold and Ascochyta was determined by visual estimation from ten consecutive plants in one row. Where white mold was present, the plant was effectively destroyed. Ascochyta infected various areas of the plant. Plots were harvested with a Hege plot combine 15 October and the grain sample cleaned and processed for yield. Data was analyzed with the general linear model (GLM) in SAS. Least significant differences (LSD) were used to compare means at the 5% probability level.

RESULTS AND DISCUSSION

No apothecia were observed from the sclerotia. The white mold that developed likely came from ascospore infection, was very aggressive, and quickly destroyed the plants that became infected. The environment was not conducive for sclerotinia development on canola and field peas in 2002 that received similar ascospore and sclerotia applications. The potential exists for losses due to white mold. The Quadris application reduced sclerotinia incidence over the Headline and Penncozeb treatments. No differences were measured in Ascochyta incidence and yield by fungicides or timings. Further fungicide research for control of sclerotinia is warranted. The untreated and a single

Tilt treatment were not included in statistical analysis 

Table1. Sclerotinia and Ascochyta incidence and chickpea yield by fungicide*timing, fungicide, and timing, Langdon 2002.

* Significant at 0.1 probability level for mean comparisons.