Date of Graduation

8-2014

Document Type

Thesis

Degree Name

Master of Science in Entomology (MS)

Degree Level

Graduate

Department

Entomology

Advisor/Mentor

Johnson, Donn T.

Committee Member

Garcia, Maria E.

Second Committee Member

Kring, Timothy J.

Keywords

Aphis Gossypii; High Tunnel; Strawberry; Tetrancyus Urticae

Abstract

Off season high tunnel strawberry production has the potential to augment income for Arkansas fruit growers during an unproductive time of the year, however management guidelines do not exist. At the University of Arkansas Agricultural Research and Extension Center in Fayetteville, AR studies were conducted to evaluate the effects of four nitrogen (46-0-0 urea fertilizer) fertigation rates (0.75, 0.50, 0.25, 0.0 kg N/day/ha) and red or black colored plastic mulch films on densities of twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), numbers of parasitized cotton aphids, and fruit yield weight. Foliar and petiole nitrogen content were evaluated in nitrogen fertigation trials. In the nitrogen fertigation experiment twospotted spider mites, cotton aphids and parasitized cotton aphids were sampled from the younger and older leaves of strawberry plants. Cowpeas, Vigna unguiculata L. Walp. (Fabales: Fabaceae), were planted and incorporated into the soil to supplement available nitrogen. Nitrogen fertigation treatments did not have the expected effect on foliar or petiole nitrogen levels. Preplanting nitrogen levels due to the cover crop of cowpeas, may have been provided sufficient nitrogen to the strawberry plants for the duration of the experiment to nullify the effect of the nitrogen treatments. Therefore, any significant differences in strawberry fruit yield, twospotted spider mite, cotton aphid, or parasitized aphid numbers would not be attributable to nitrogen fertigation treatments, and none were found. There were no significant differences among nitrogen fertilization treatments in the numbers of twospotted spider mites on the younger or older leaves except for one sample date, 8 January. However there were significantly more cotton aphids and parasitized cotton aphids in the older leaves compared to the younger leaves. There were no significant differences in strawberry fruit yield, twospotted spider mite, cotton aphid, or parasitized cotton aphids in the red or black plastic mulch experiment, although lack of sufficient replication limited results. Future experiments may compare interaction effects of several high tunnel plastic film covers with different light transmitting characteristics and different color mulches on strawberry yields and aphid and mite densities inside high tunnels versus in open fields.

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