Herbicide-Root Rot Interaction in Navy Bean

Abstract

Navy bean (Phaseolus vulgarisL.) seedlings grown in soil treated with EPTC (S-ethyl dipropylthiocarbamate) were more susceptible to root rot caused byFusarium solani(Mart.) Appel and Wr. f.phaseoli(Burk.) Snyd. and Hans. than were control seedlings. The navy bean line ‘RRR041,’ which is moderately resistant to root rot, did not show reduced growth when grown in soil infested withF. solaniand treated with EPTC. None of the several herbicides tested increasedF. solanichlamydospore virulence when grown on potato dextrose agar supplemented with herbicides. No herbicide tested increasedF. solanihyphal development in liquid culture or soil. Dinoseb (2-sec-butyl-4,6-dinitrophenol) reduced hyphal development by the greatest amount. Scanning electron micrographs indicated that navy bean plants grown in EPTC had altered hypocotyl surfaces. EPTC and dinoseb increased the exudation of electrolytes, amino acids, and sugars from root and hypocotyl tissue.

Mechanism for the Suppression of pea (Pisum sativum) Root Rot by Dinitroaniline Herbicides

“…Table 2 shows that oryzalin and trifluralin had no significant effect on exudates from pea roots. Wyse et al (26) showed very similar results for the effect of trifluralin on navy bean root exudates. Thus, pea root rot suppression by dinitroaniline herbicides cannot be explained by a reduction in pathogen activity due to reduced root exudation.…”

“…Effect of dinitroaniline herbicides on exudation from pea roots. Herbicides have been reported to increase root diseases of a number of crops due to a stimulation of root exudates by those herbicides (1,16,26). Therefore, even if herbicides do not affect the resistance of a host to direct pathogen invasion, they may alter root exudation thereby altering pathogen activity in the rhizosphere.…”

“…Of all fungi studied to date, A. euteicbes is the most sensitive to dinitroaniline herbicides. The mycelial growth of most plant pathogens is not affected significantly by dinitroaniline herbicides at field rates of application (6,7,14,20,23,26). Dinitroaniline herbicides have been reported to alter the resistance of some crops to plant diseases.…”

Prevention of EPTC—Induced Epicuticular Wax Aggregation on Corn (Zea mays) with R-25788

“…capitata L.) (3,4,5), and navy bean (Pbaseolus vulgaris L.) (12). This inhibition has been associated with EPTC •induced predisposition of navy bean to root rot caused by Fusarium solani (Mart) Appel (12,13). EPTC also has been reported to inhibit lipid synthesis in isolated spinach (Spinacia oleracea L.) chloroplasts (11).…”

Suppression of Root Diseases and Weeds in Peas(Pisum sativum)Treated with Dinitrophenol and Dinitroaniline Herbicides

“…Both suppression and intensification of diseases are re ported. Wyse et al (16,17) showed increased F. solani f. sp. phaseoli disease severity in navy bean (Phaseolis vulgaris L.) and reduced yields after EPTC (S-ethyl dipropylthiocarbamate), chloramben (3-amino-2,5-dichlorobenzoic acid), and fluorodifen (p-nitrophenyl a,a,a-trifluoro-2nitro-p-tolyl ether) treatments.…”