The effect of beta-caryophyllene derivatives in a tri-species cotton hybrid on cotton aphid infestation and population growth potential

Authors: ALLISON, RAVEN - Texas A&M University; Suh, Charles; HAGUE, STEVEN - Texas A&M University; KERNS, DAVID - Texas A&M University

Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/15/2023
Publication Date: 12/1/2023
Citation: Allison, R.S., Suh, C.P.-C., Hague, S., Kerns, D.L. 2023. The effect of beta-caryophyllene derivatives in a tri-species cotton hybrid on cotton aphid infestation and population growth potential. Southwestern Entomologist. 48(4):771-780. https://doi.org/10.3958/059.048.0402.
DOI: https://doi.org/10.3958/059.048.0402

Interpretive Summary: Cotton production in the U.S. has relied heavily on insecticides to manage aphids in cotton but aphid populations are becoming increasingly resistant to these chemicals, and aphid-specific toxins produced by genetically modified plants do not exist. Thus, there is a critical need to identify alternative pest management strategies for aphids in cotton. One such strategy may involve host plant resistance, whereby plants naturally produce compounds that adversely insect populations. In previous work, ARS scientists developed a hybrid cotton plant that produces three unique compounds. A series of field, laboratory, and greenhouse experiments were conducted to assess how plants expressing these compounds affected aphid colonization and reproduction. Our findings revealed that plants expressing one of the compounds negatively affected aphid colonization and reproduction on cotton plants. Efforts are underway to increase seed production for large-scale field trials.

Technical Abstract: Currently, insecticide applications and genetically-modified plants expressing Bacillus thuringiensis (Bt) toxins are the primary means for managing insect pests in cotton, but many of these pests have developed resistance to Bt technologies and pesticides. Because of resistance, host plant resistance may be a viable solution to help prevent significant yield losses. Tri-species cotton hybrids consisting of either Gossypium hirsutum L., G. arboreum, and G. armouranium, or G. hirsutum, G. arboreum, and G. turneri have been reported to produce ß-caryophyllene derivatives (12-hydroxy-ß-caryophyllene and hydroxy-ß-caryophyllene acetate) and have demonstrated resistance to nematodes, drought, and heat stress. Yet, there is a lack of evidence whether these hybrids affect cotton insect pests. A series of field, greenhouse, and laboratory experiments were conducted to assess the impact a tri-species cotton hybrid expressing ß-caryophyllene or its alcohol and acetate derivatives, have on cotton aphid, Aphis gossypii Glover. Although inconclusive in field trials, greenhouse choice test revealed the tri-species hybrid cotton had less colonization and fewer alate cotton aphids than G. hirsutum. Furthermore, in a cotton aphid reproduction study, the intrinsic rate of increase and finite rate of increase were lower for aphids feeding on the tri-species hybrid plants expressing ß-caryophyllene or its alcohol derivative compared with G. hirsutum. Results suggest that the tri-species cotton hybrid, especially those capable of expressing the ß-caryophyllene alcohol derivative, negatively impacts the cotton aphid population development.