Pest density influences on tomato pigment contents: the South American tomato pinworm scenario

摘要

It has long been hypothesized that there is a relationship between pigment content of host plant and pest densities. This study aimed to assess the amount of tomato carotenoid, chlorophyll content and leaf area damage in response to different levels of damage caused by the South American tomato pinworm, Tuta absoluta (Meyrick) (Lepodoptera: Gelechiidae). The results confirmed the effect of pest density on chlorophyll a, b, a+b, and carotenoids contents were all significant in the first year of study. During the second year, the effect of T absoluta treatments on chlorophyll "a", "b", "a+b" and on carotenoids was significant. The highest and lowest values of pigment content were recorded in control and plant treatments of eight T absoluta eggs in the first year and plant treatments of sixteen eggs in the second year, respectively. The results of leaf loss assessment demonstrated a significantly different consumed leaf area across the different densities of T absoluta eggs in both years. The results are useful in gaining an oversight of pest density influences on tomato pigment content. By estimating the reduction of the pigments content and or reducing the green tissue of the plant and its relationship with the pest density, damage can be prevented before it reaches the economic injury level.