A Plant-by-Plant Method to Identify and Treat Cotton Root Rot Based on UAV Remote Sensing

Tianyi Wang,Chenghai Yang,J Alex Thomasson,Thomas Isakeit,Robert L Nichols

doi:10.3390/rs12152453

Abstract

Cotton root rot (CRR), caused by the fungus Phymatotrichopsis omnivora, is a destructive cotton disease that mainly affects the crop in Texas. Flutriafol fungicide applied at or soon after planting has been proven effective at protecting cotton plants from being infected by CRR. Previous research has indicated that CRR will reoccur in the same regions of a field as in past years. CRR-infected plants can be detected with aerial remote sensing (RS). As unmanned aerial vehicles (UAVs) have been introduced into agricultural RS, the spatial resolution of farm images has increased significantly, making plant-by-plant (PBP) CRR classification possible. An unsupervised classification algorithm, PBP, based on the Superpixel concept, was developed to delineate CRR-infested areas at roughly the single-plant level. Five-band multispectral data were collected with a UAV to test these methods. The results indicated that the single-plant level classification achieved overall accuracy as high as 95.94%. Compared to regional classifications, PBP classification performed better in overall accuracy, kappa coefficient, errors of commission, and errors of omission. The single-plant fungicide application was also effective in preventing CRR.

Highlights

The United States (U.S.) produced 20.9 million 218-kg (480-lb) bales of cotton in the 2017–2018 season with a production value of $7.2 billion (USD), ranking 3rd after India and China, and it is the largest cotton-exporting country in the world [1]
The disease is caused by the soilborne fungus, Phymatotrichopsis omnivora, a destructive plant disease throughout the southwestern U.S The first documented study of cotton root rot (CRR) was in the 19th century by Pammel [2]
This study shows that CRR-infected plants in the current season can be individually identified with high accuracy, and PBP fungicide treatment appears to be effective in controlling CRR

Summary

Introduction

The United States (U.S.) produced 20.9 million 218-kg (480-lb) bales of cotton in the 2017–2018 season with a production value of $7.2 billion (USD), ranking 3rd after India and China, and it is the largest cotton-exporting country in the world [1]. The state of Texas produced 9.5 million bales, approximately 44% of U.S cotton production, ranking 1st in the U.S [1]. While Texas is by far the largest producing state, a major obstacle to cotton production in Texas is a disease called cotton root rot (CRR) or Texas root rot. If the disease develops in an early stage of growth, the plants will die before bearing fruit. If it develops after flowering, the disease will reduce yield and lower the quality of the cotton lint by stopping transport of nutrients to the maturing bolls

Methods

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Discussion

Conclusion