Pest Control In Commercial Agriculture
Research in biological pest management in agroecosystems and general plant crops is one of the essential parts of ensuring a viable crop yield as well as sustainability of the crop field and the surrounding environment. Involving myself in specialized research with pests that cause substantial crop damage and problems in urban areas in Texas is something I have already started and thoroughly enjoy. The passage of the Food Quality Protection Act (FQPA) and more rigorous practices of the U. S. Environmental Protection Agency (EPA) have since pressed the concern for the safety of children and American families (Wheeler).
Integrated pest management in agriculture has rapidly developed over the past 50 years with the research, creation, and technical application of synthetic organic materials and biopesticides (Wheeler). Biological pest control with emphasis on the use of natural enemies goes along with the want for the relative safety of human health as opposed to the use of broad-spectrum pesticides. Different natural enemies can be introduced; parasites, pathogens, and predators are mostly specialized to a closely related pest species. Working with host-specific natural enemies ultimately is low-risk and provides great benefits.
My research with the Texas A&M University has the central theme of grain sorghum (Sorghum bicolor) crop protection from sugar cane aphids (SCA), Melanaphis sacchari, by understanding the proposed mutualisms between SCA and invasive ant species, such as tawny crazy ants (Nylanderia fulva). Ant-aphid mutualisms have been observed in situations of low available resources and population densities. This relationship provides limited protection for the aphids and a consistent nutrition source for the ant colony. Ant-aphid mutualisms can be detrimental in agricultural ecosystems. Native parasitoids along with simulated drought may help increase grain sorghum yield in the state of Texas while decreasing regional SCA populations.
SCA is a relatively new pest to the southern United States, only first reported in the Lower Rio Grande Valley in 2013. Within the next two years, SCA would reach seventeen states in areas that make up approximately 90 percent of total United States acreage of sorghum production. Adult aphids live for approximately four weeks. Their colonies initially have few individuals but most colonies grow relatively fast covering the entire underside of a host plant’s leaf in X days. A single plant can host a population of up to 30, 000 aphids. Winged adults, alates, appear in cases of food shortage and use wind-aided flight to travel distances between fields or as far as Mexico to North Texas. This makes SCA a substantial and costly horticultural pest. In Texas alone, 2. 7 million acres of sorghum (7 million total in the United States) with an estimated value of $742. 7 million is planted each year. Sugarcane aphids, while they do not inject a toxin into their host plant, do cause yellowing that eventually leads to the decomposition of plant tissue. The honeydew residue produced by the aphids can propagate the growth of a black mold that will inhibit the light absorption of the plant.
Infestations of sugarcane aphids can cause millions of dollars of revenue loss due to loss of the crop itself, complete germination prevention, or damage to equipment due to the aphids secretion of honeydew. In the US sugarcane aphids feed and reproduce on grain sorghum and forage sorghums, including Sudan grass, sorghum/Sudan hybrids, and Johnson grass. All of these hosts are in the genus Sorghum. Preferred conditions for sugarcane aphids are the warm temperatures of summer. Colonies can still be found during the winter and spring on Johnson grass and sorghum. To combat the infestations and increase protection from profit loss, growers of sorghum have developed hybrids that are genetically modified to be resistant to sugarcane aphids. Modified watering plans may also be an infestation preventative measure. Short stress periods in grain sorghum propagation are a preventative measure that allows an acceptable crop yield. This, along with selective pesticides and predatory insects as biological control agents are the beginnings of controlling this mounting pest problem.
Aphid parasitoids are 1/10 inch long moths whose females lay their eggs inside the aphids. The larva will eventually hatch and develop within the aphid eventually killing it. Some larvae may chew a hole in the rear of the aphid to escape or pupate beneath the aphid. The aphid body will eventually become a “mummy” which are bloated, brown/black remains of the aphid that was.
Understanding under which conditions sugarcane aphids thrive can help sorghum producers to acclimate crops and begin using methods that would aid in controlling sugarcane aphid populations. Growth management plans such as frequency of watering and light exposure may create an environment unsuitable for the local aphid but can still sustain the plant. Region and sugarcane aphid genotype specific growing practices would be pertinent in preventative and controlled pest management in commercial agriculture.
