Crop signal markers facilitate crop detection and weed removal from lettuce and tomato by an intelligent cultivator

Abstract

Increasing weed control costs and limited herbicide options threaten vegetable crop profitability. Traditional interrow mechanical cultivation is very effective at removing weeds between crop rows. However, weed control within the crop rows is necessary to establish the crop and prevent yield loss. Currently, many vegetable crops require hand weeding to remove weeds within the row that remain after traditional cultivation and herbicide use. Intelligent cultivators have come into commercial use to remove intrarow weeds and reduce cost of hand weeding. Intelligent cultivators currently on the market such as the Robovator, use pattern recognition to detect the crop row. These cultivators do not differentiate crops and weeds and do not work well among high weed populations. One approach to differentiate weeds is to place a machine-detectable mark or signal on the crop (i.e., the crop has the mark and the weed does not), thereby facilitating weed/crop differentiation. Lettuce and tomato plants were marked with labels and topical markers, then cultivated with an intelligent cultivator programmed to identify the markers. Results from field trials in marked tomato and lettuce found that the intelligent cultivator removed 90% more weeds from tomato and 66% more weeds from lettuce than standard cultivators without reducing yields. Accurate crop and weed differentiation described here resulted in a 45% to 48% reduction in hand-weeding time per hectare.

Robotic weeders can improve weed control options for specialty crops

“…CRISPR technology could be used to breed for a marker in the crop that has spectral reflectance at a wavelength found only in the crop . Another strategy would be to place a physical marker on the crop before or during transplanting which would ease machine recognition Improved physical weed control actuators.…”

“…Use of a flurochrome marker placed on lettuce leaves or tomato stems allowed for a prototype machine vision system to accurately detect crop location and to remove weed near the crop with an intra‐row cultivator even in very weedy situations (Fig. ) …”

“…Use of physical crop markers, such as a plant tag placed on the vegetable transplant to improve weed crop differentiation is an active area of research (Fig. ) . Thus far, engineered herbicide resistance, CRISPR, transgenic or conventional breeding has yet to have any impact on specialty crops weed programs.…”

Near‐term challenges for global agriculture: Herbicide‐resistant weeds

“…Just as with herbicide applications, timing and number of treatments needed for acceptable control are important considerations (Cordeau et al., 2017; Erazo‐Barradas et al., 2018; Ulloa et al., 2010). Depending on the technology involved, the machines can be expensive (having machine vision, controllers, and computers for guidance and making on‐the‐go decisions) (Kennedy et al., 2020) and time consuming (due to slow travel speeds) (Erazo‐Barradas et al., 2018; Kennedy et al., 2020; Ulloa et al., 2010). Mechanical innovations, including drones, robotics devices (e.g., Robovator, Steketee, Teretill), and artificial intelligence technologies that recognize target weeds in the crop, will be integrated into future weed control strategies (Steward et al., 2019; Young et al., 2014; Westwood et al., 2018).…”

Systemic Crop Signaling for Automatic Recognition of Transplanted Lettuce and Tomato under Different Levels of Sunlight for Early Season Weed Control

“…In a recent study, ultraviolet (UV) fluorescence imaging was used for the accurate detection of aflatoxin in corn kernels [31]. In addition, topical markers and plant labels directly applied to the foliage or stem of vegetable plants including tomato and lettuce were successfully detected based on this imaging technology [32].…”