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Title: RESISTANCE OF TRIPSACORN TO STORAGE INSECT PESTS

Author
item Throne, James
item EUBANKS, MARY - DUKE UNIVERSITY

Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/9/2001
Publication Date: 2/1/2002
Citation: THRONE, J.E., EUBANKS, M.W. RESISTANCE OF TRIPSACORN TO STORAGE INSECT PESTS. JOURNAL OF STORED PRODUCTS RESEARCH 38: 239-245. 2002.

Interpretive Summary: The maize weevil is one of the most serious insect pests of maize during storage. A hybrid (called Tripsacorn) between Tripsacum dactyloides and Zea diploperennis was shown to be immune from attack by maize weevils because female maize weevils were unable to lay eggs in the Tripsacorn kernels. Tripsacorn kernels are enclosed in a hard shell-like fruitcase, and we hypothesized that weevils did not lay eggs in the Tripsacorn becaus of the hardness of the fruitcase. Sawtoothed grain beetles were able to complete immature development on ground Tripsacorn, but duration of development was longer and weight of emerged adults was less than for beetles developing on wheat. It remains to be determined what the mechanism of immunity to maize weevils exhibited in Tripsacorn is and if it can be incorporated into commercial maize hybrids.

Technical Abstract: A hybrid (called Tripsacorn) developed from a perennial teosinte, Zea diploperennis, and eastern gamagrass, Tripsacum dactyloides, was evaluated for resistance to storage insect pests. Tripsacorn resembles the earliest known samples of primitive maize. We tested resistance of whole Tripsacorn to the primary storage pest (primary storage pests can infest intact kernels) the maize weevil, Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae), and resistance of ground Tripsacorn to the secondary storage pest (secondary pests usually cannot infest intact kernels) the sawtoothed grain beetle, Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae). Tripsacorn was immune to attack by S. zeamais. The weevils were unable to lay eggs in the Tripsacorn, and we hypothesized that the hardness of the fruitcase was responsible for lack of weevil oviposition. O. surinamensis were able to complete immature development on ground Tripsacorn, but duration of development was longer and weight of emerged adults was less than for beetles developing on wheat. It remains to be determined what the mechanism of immunity to maize weevils exhibited in Tripsacorn is and if it can be incorporated into commercial maize hybrids.