TITLE:
Tri-Trophic Interactions within Potato Agro-Ecosystem, Qassim, KSA
AUTHORS:
Wafa A. Alkherb, Nagdy F. Abdel-Baky, Mohammad A. Aldeghairi
KEYWORDS:
Tri-Trophic Interactions, Fertilizers, Potato Plants, Cotton Aphids, Beneficial Insects
JOURNAL NAME:
Agricultural Sciences,
Vol.7 No.12,
December
27,
2016
ABSTRACT: Tri-trophic interactions between fertilizer applications, cotton aphid (Aphis gossypii Golver) and associated beneficial insects were studied to investigate direct and indirect effects of fertilizers (types and ratios) on potato plants under field and greenhouse conditions, A. gossypii and associated beneficial insects. Fertilizers regimes showed direct impacts on the potato plant phenology and indirect effects on both A. gossypii population and the associated beneficial insects. Our data indicated that potato plants had been influenced by fertilizer elements used within tri-trophic system comprising potato plants, cotton aphid, and certain associated beneficial insects. This demonstrates that a bottom-up interaction is robust and has a particular value in the attraction of beneficial insects towards the potato plant signals due to used fertilizers which can also have a function when plants are attacked by A. gossypii. Yet, flexibility in the use of fertilizers (as chemical cues) is conserved, and that may help beneficial insects to specifically focus on the odor of plants that carry potential plant hosts and avoid plants that are only attacked by non-hosts. These results support the still controversial notion that fertilizer elements, at least in part, help plants to serve as functional signals to attract the enemies of the harmful insects. These observations declare the benefits of the tri-trophic interactions as an ecological phenomenon in particular and the food chain in general. Additionally, this study may be useful to be used as a predictable model with the associated beneficial insects which may have key roles in overall aphid suppression or regulating its population. Impact of fertilizers on potato phenology characteristics and the cotton aphid population density seems to be variable based on types and ratios of the fertilizers. Interfacing the impact of natural enemies (plant-pest-natural enemies) through tri-trophic relationship within the food chain verified to be straightforward way of predicting on the impact of beneficial insects-guild on the cotton aphid population density.