Economic Evaluation of the Effects of Planting Date and Application Rate of Imidacloprid for Management of Cereal Aphids and Barley Yellow Dwarf in Winter Wheat

Abstract

The effects of planting date and application rate of imidacloprid for control of Schizaphis graminum Rondani, Rhopalosiphum padi L. (Homoptera: Aphididae), and barley yellow dwarf virus (BYDV) in hard red winter wheat were studied. The first experiment was conducted from 1997 to 1999 at two locations and consisted of three planting dates and four rates of imidacloprid-treated seed. The second experiment was conducted from 2001 to 2002 in Stillwater, OK, and consisted of two varieties of hard red winter wheat seed and four rates of imidacloprid. Aphid densities, occurrence of BYDV, yield components, and final grain yield were measured, and yield differences were used to estimate the economic return obtained from using imidacloprid. In the first study, aphid populations responded to insecticide rate in the early and middle plantings, but the response was reduced in the late planting. Yields increased as insecticide rate increased but did not always result in a positive economic return. In the second study, imidacloprid seed treatments reduced aphid numbers and BYD occurrence, protected yield, and resulted in a positive economic return. The presence of aphids and BYDV lowered yield by reducing fertile head density, total kernel weight, and test weight. Whereas the application of imidacloprid seed treatments often provided positive yield protection, it did not did not consistently provide a positive economic return. A positive economic return was consistently obtained if the cereal aphid was carrying and transmitting BYDV and was more likely to occur if wheat was treated with a low rate if imidacloprid and planted in a "dual purpose" planting date window.

REVIEW: An overview of the environmental risks posed by neonicotinoid insecticides

“…Similarly, studies of the efficacy of imidacloprid dressing of winter wheat in North America suggest that yield benefits are small (compared to unprotected, control crops) and often exceeded by the cost of the pesticide (Royer et al . ). In contrast, in Western Australia, McKirdy, Jones & Nutter () demonstrated that application of an imidacloprid seed dressing to spring wheat is cost‐effective compared to using no pest control, but that using foliar applications of alpha‐cypermethrin (which is much cheaper) provided a significantly higher economic return.…”

The complete nucleotide sequence of the genome of Barley yellow dwarf virus-RMV reveals it to be a new Polerovirus distantly related to other yellow dwarf viruses

“…Perry et al (Perry et al, 2000) found an average of 30% yield loss in affected winter wheat fields. Significant agricultural research efforts are aimed at reducing the impact of the YDVs on the yield of the various crop systems by (i) altering planting time and/or pesticide application regimes to avoid the accumulation of high densities of aphids, (ii) tilling practices, and (iii) developing virus-resistance crop varieties (Chain et al, 2005; Royer et al, 2005; Kennedy and Connery, 2012). …”

Protective effect and economic impact of insecticide application methods on barley

“…For the conditions of the year 2011, the ST and the control treatment without insecticide application showed the best return; however it is important to note that there was a lower aphid population in 2011, and there was no statistical difference between treatments for yield. This same advantage was cited by Royer et al (2005), who mentioned that the ST with insecticide, as imidacloprid for instance, has certain economic and environmental qualities, such as low utilization rates (low doses per target), low exposure to the applicator and the prevention of cultures to virus. In 2011, among all the costs of each treatment, the cost of insecticide (product + application) was equivalent to 13.5% of total expenditures in T1, 6% in T2, and 1% in T3.…”