Designing a Better Sprayer for Pesticide Application in Strawberries
Strawberry growers using conventional boom sprayers find it difficult to obtain good disease and insect control due to poor pesticide coverage on the undersides of leaves, on the lower leaves, and on the fruit when the strawberry plant is in full canopy. Inadequate crop protectant coverage results in higher levels of disease and insect activity translating to consumer rejection of poor quality fruit and lower overall profitability of the planting. This project focused on spray systems for strawberries – a high value crop with a low, 3-dimensional canopy. Strawberry diseases are a big concern for growers, so adequate spray coverage is important – better coverage would allow growers to make fewer applications of fungicides during the growing season.
Drift is often identified as being the biggest source of problems with spray deposition. In fact there are other, inter-related factors that combined with drift, make designing the perfect crop protectant delivery system a challenge. These include the sprayer design, the droplet size and the size of the spray fan. The air volume, direction and velocity will also affect the amount of material that is deposited vs. the amount that is lost to drift. Application rate, nozzle orientation and the speed of the tractor, plus the skill and attitude of the tractor operator are also factors. Additionally the crop canopy will determine deposition rate and the weather also has a great deal of influence.