Submitted to: Extension Service Bulletins
Publication Type: Experiment Station
Publication Acceptance Date: 5/1/1998
Publication Date: N/A
Technical Abstract: Dry hot weather has caused insects, rats, and other pests to migrate to rice field water and vegetation. Irrigation problems caused by weather extremes have resulted in poor weed control, loss of nitrogen, salt problems, and plant stress in some cuts and fields. Rice plants under water stress lose some inherent disease resistance. Although dry conditions generally have reduced disease incidence, water stressed areas should be monitored closely as these areas may be more disease prone. High temperatures can result in rapid sheath blight development. Day temperatures above 95 degrees F and night temperatures above 75 degrees F can cause damage to rice. The most sensitive rice stage to high temperatures is heading/pollination, although damage can occur at any time during the reproductive phases of plant development (pd and after). After fields have reached the reproductive stages field flood depths should be increased to prevent moisture stress and to lower the temperature in fields. Fields must be kept FLOODED after the reproductive stage to minimize stress. Hot dry winds desiccate emerging florets, resulting in partial blanking of the panicle. If blanking is not severe, the plant can compensate by filling more grain at the base of the panicle and filling grain more completely. Blanking greater than 10 percent can reduce yield of the affected heads. Key concerns are 1) don't let fields become nitrogen deficient, 2) avoid moisture stress as much as possible, especially in fields which are in the reproductive stages of development, 3) monitor fields closely for diseases especially in areas that had been water stressed, and 4) monitor fields closely for insects and other pests.