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Cotton Leaf Surface Features Serve as Behavioral Cues to the Silverleaf Whitefly

Allen Carson Cohen, Chang-chi Chu, T.J. Henneberry, Thomas Freeman, James Buckner, Dennis Nelson


We examined cotton leaves looking for correlations between surface structures and veins, using light and electron microscopy. Using placement of eggs, nymphal positions and crawler (1st instar nymph) behavior, we evaluated the responses of whitefly nymphs to the surface features. We found that all aerial trichomes originated from epidermal cells immediately lower or upper to veins, including a hairy cotton isoline DPL 115 containing 48 (+/- 2.5) trichomes/ cm2. Leaf surface microstructures such as elongated epidermal cells were always evident wherever veins were present, including even the most minute bundles (single-stranded). Of 2000 aerial trichomes (non-glandular) that were examined, 100% originated from vein-associated epidermal cells. Eggs were generally deposited on the elongated epidermal cells associated with bundles or on cells within about 30 microns of those bundle-associated epidermal cells. Crawlers walked about 2300 microns per minute until they settled upon feeding sites that were immediately under the veins, never more than about 60 microns from the center of the lower bundle-associated epidermal cells. Crawlers spent at least 80% of their time in contact with bundle-associated epidermal cells, making contact with these cells either with legs or antennae.

Reprinted from Proceedings of the 1996 Beltwide Cotton Conferences pp. 1017 - 1020
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998