HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Moffett, J. O. Articles by Shipman, C. W. Search for Related Content PubMed Articles by Moffett, J. O. Articles by Shipman, C. W. Agricola Articles by Moffett, J. O. Articles by Shipman, C. W.

Effect of 2,4-D on Cotton Yield, Floral Nectar, Seed Germination, and Honeybee Visits

In Arizona honey bees, Apis mellifera L., frequently visit cotton flowers, Gossypium hirsutum L., in sufficient numbers to adequately pollinate the male sterile flowers and produce hybrid cotton seed. Yet in some other states and at times in Arizona, honey bee visits to cotton flowers are low or erratic. Since hybrid cotton seed may be in demand in the near future, this study was made to determine how spraying 2,4-D [(2,4-dichlorophenoxy) acetic acid] on cotton plants affected honey bee visits, seed yields, and nectar secretion.

Small concentrations of 2,4-D were sprayed on five cotton cultivars at three locations in Arizona from 1975 to 1977. Each year, 1 ppm applied in 187 liters of water/ ha at the beginning of bloom increased the volume of floral nectar more than 30%. An application of 10 ppm was harmful to the plants. Application of 2,4-D when plants started to flower increased the amount of nectar more than application 3 weeks earlier or application at both times. One ppm of 2,4-D had no significant effect on cotton yields or sugar concentration of the floral nectar.This dosage also had no significant effect on honey bee visits during the only year, 1977, that visits were counted. However, this year the visits were relatively high in both the check and unsprayed plots. Results might be different when the bees are not visiting the flowers well. None of the levels of 2,4-D applied (0.01, 0.1, 1.0, and 10.0 ppm) affected germination or weight of the seeds produced or caused damage to seedlings grown from the sprayed plants.

Key Words: Apis mellifera L. • Gossypium hirsutum L. • Hybrid cotton • Pollination • Nectar secretion

² Professor of plant science, Univ. of Arizona, Tucson, AZ 85721.

³ Plant physiologist, Carl Hayden Bee Research Center, AR, SEA, USDA, 2000 E. Allen Road, Tucson, AZ 85719. 4

⁴ 4 Biological technician, Carl Hayden Bee Research Center, AR, SEA, USDA, 2000 E. Allen Road, Tucson, AZ 85719.

Received for publication April 4, 1980.