Weed control effect of unmanned aerial vehicle (UAV) application in wheat field

Abstract

Wheat is a major food source throughout the world.  However, biological factors like pests and weeds can lead to lower crop yield. Most crop protection nowadays involves pesticide and herbicides application. This is commonly conducted with knapsack in China, which is inefficient and high labor intensive. Unmanned aerial vehicle (UAV) are an aerial spraying technology recently-developed. Using UAV application is more flexible and standardized, the spraying efficiency is 60 times more than knapsack sprayer. However, weed management using UAV is still a challenge. Low spray volume and droplet density with less penetration may affect weed control efficacy. High droplet concentration may induce crop injury. This study focused on discovering crop safety and weed control efficacy of UAV in wheat fields. Different herbicides, rates and spray volume were tested for pre-emergence (PRE) and post-emergence (POST). The results show that no crop injury was induced for PRE. While 10%-20% injury on wheat was found for POST. All herbicides treatments showed significant effects on weed management compared to untreated control. However, the efficacy was not stable between years and fields. Weed management for PRE can reach 98%-100% when the soil is humid, smooth and with no straw coverage when using diflufenican + isoproturon (120 + 1200 g ai ha -1 ). For POST application via UAV, weed injury ranged from 10% injury to 70%, in which isoproturon + clodinafop-propargyl + mesosulfuron (120 + 7.5 + 0.9 g ai ha -1 ) injured weed the most in 2018 (reached 70%). Knapsack sprayer showed relatively better weed control efficacy in many cases for POST applications. Weeds showed certain degree of resistance. In general, PRE application with UAV showed better potential, but herbicide spraying needs to be combined with field management to achieve better weed management efficacy. Keywords: unmanned aerial vehicle (UAV), herbicide application, weed management, wheat DOI:  10.33440/j.ijpaa.20190202.45.  Citation: Chen Y, Qi H L, Li G Z, Lan Y B.  Weed control effect of unmanned aerial vehicle (UAV) application in wheat field.  Int J Precis Agric Aviat, 2019; 2(2): 25–31.