Non Destructive Technology

Tomato Bacterial Speck And Spot Detection With Machine Vision Computed Plant Features In Controlled Environments

1. Introduction

Climate change has made many farmers suffered losses and led to the uncertainty of planting and harvesting time. Controlled-environment agriculture (CEA) is an integrated science and engineering approach to horticultural technology with the aim of enabling crop production in controlled environments that might otherwise be unfavorable for agriculture (Story et al, 2010).

The demand for fresh vegetables has significantly increased over the last 20 years in the US (Nzaku and Houston, 2009). Tomato (Lycopersicon esculenturn Mill.) is one of the most important fresh vegetables (Van Sickle, 2008). One technique that is developed for tomato production is hydroponic system. In addition to field production, greenhouse tomato production has rapidly increased since 2005, accounting for 37% of the total fresh market volume in the US (Cook and Calvin, 2005).

A drawback to this hydroponic system is that the grower cannot access all areas of the growing space to monitor the status of the tomato crop. One such issue that requires close monitoring is tomato bacterial speck and spot. Bacterial speck of tomato, caused by Pseudomonas syringae pv. tomato, and bacterial spot of tomato, caused by Xanthomonas campestris pv. vesicatoria and Xanthomonas vesicatoria, are among the most economically important bacterial diseases in many tomato-growing regions of North America and the world (Goode and Sasser, 1980). Lesions occur on leaves and may cause an entire leaflet to turn yellow and drop. As the diseases progress, the lesions may spread to stems, petioles, and flowers. Yield reductions can result from the reduced photosynthetic capacity of infected foliage, leaf defoliation, flower abortion, and from lesions on the fruit that render them unsuitable for the fresh market or for processing. Bacterial speck is more severe under cool and humid...