Speckback, a small imperfection that occurs on the dorsal surface (the surface opposite the germ) of kernels of rice (Oryza sativa L.), is characterized by a variety of lesions, not all of which are discernible by the unaided eye and, therefore, are unlikely to be detected by inspectors in industry. Speck back has been known for years but was so rare and inconspicuous that it was not considered a problem. A sudden, dramatic increase in the incidence of speckback coincided with the release of the high-yielding, semidwarf, long-grain cultivars Lemont and Gulfmont. The superficial resemblance to peck, damage associated with the rice stink bug, Oeba/us pugnax (F.), fostered suspicion that insects caused speck back. This imperfection, far more abundant in 'Lemont' and 'Gulfmont' than in other cultivars, was unaffected by chemical control of insects in commercial fields or test plots, by confining heavy infestations of insects with piercing-sucking mouthparts on rice panicles, by deliberate exclusion of all insects, or by stress (sheath blight) induced by the disease. Excessive or lIuctuating levels of irrigation water increased the incidence of speck back somewhat but was not the sole determining factor. Regardless of insect infestation or control, speck back was 3.8 times more abundant in ratoon-crop and 5.9 times more abundant in late-planted rice than in main-crop rice seeded on a normal planting date. There was no evidence that speck back was caused by or associated with insects.
Document Type: Research Article
Publication date: June 1, 1991
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Journal of Economic Entomology is published bimonthly in February, April, June, August, October, and December. The journal publishes articles on the economic significance of insects and is divided into the following sections: apiculture & social insects; arthropods in relation to plant disease; forum; insecticide resistance and resistance management; ecotoxicology; biological and microbial control; ecology and behavior; sampling and biostatistics; household and structural insects; medical entomology; molecular entomology; veterinary entomology; forest entomology; horticultural entomology; field and forage crops, and small grains; stored-product; commodity treatment and quarantine entomology; and plant resistance. In addition to research papers, Journal of Economic Entomology publishes Letters to the Editor, interpretive articles in a Forum section, Short Communications, Rapid Communications, and Book Reviews.