abstract- the evaluation of leaf area and leaf nutritional value is important for crop growth modeling and estimations of its performance. the purpose of this study was to use image processing techniques to develop an economical method to ease the assessment of nutrient status and leaf area (la) of plants and to compare the outcomes of this method with linear models. leaf area and leaf chloroph...

Almond leaf scorch (ALS) disease has emerged recently as a serious threat to almond production areas throughout California’s San Joaquin Valley (5,36). This disease is caused by the xylem-limited bacterium Xylella fastidiosa, which also causes several plant diseases in California including Pierce’s disease (PD) of grape, oleander leaf scorch (OLS), and alfalfa dwarf (AD). X. fastidiosa bacteria...

The objective of this study was to develop a rapid non-destructive technique to estimate total chlorophyll (Chl) content in a maize canopy using Chl content in a single leaf. The approach was (1) to calibrate and validate a reflectance-based non-destructive technique to estimate leaf Chl in maize; (2) to quantify the relative contribution of each leaf Chl to the total Chl in the canopy; and (3)...

this study was performed to investigate the effect of putrescine and spermine on some physiological and biochemical characteristics and antioxidant enzymes activity of peach (prunus persica cv. alberta) and almond (prunus dulcis cv. rabi) seedlings under water deficit. the first factor was water regime at two levels (80% or 50% of soil available water), and the second factor was polyamine treat...

Grapevine red blotch disease (GRBD) is an emerging caused by grapevine virus (GRBV). It widespread in most United States winegrape production regions and differential spread dynamics have been reported between the regions. This study surveyed eight vineyard sites southern Oregon over four years for progression of GRBD incidence. The vineyards included five that were or older three three-years-o...

BACKGROUND AND AIMS Kaolin applications have been used to mitigate the negative effects of water and heat stress on plant physiology and productivity with variable results, ranging from increased to decreased yields and photosynthetic rates. The mechanisms of action of kaolin applications are not clear: although the increased albedo reduces leaf temperature and the consequent heat stress, it al...

BACKGROUND AND AIMS Crop protection strategies, based on preventing quantitative crop losses rather than pest outbreaks, are being developed as a promising way to reduce fungicide use. The Bastiaans' model was applied to winter wheat crops (Triticum aestivum) affected by leaf rust (Puccinia triticina) and Septoria tritici blotch (STB; Mycosphaerella graminicola) under a range of crop management...

Several theories exist about the role of anthocyanins in senescing leaves. To elucidate factors contributing to variation in autumn leaf anthocyanin contents among individual trees, we analysed anthocyanins and other leaf traits in 27 individuals of red maple (Acer rubrum L.) over two growing seasons in the context of timing of leaf senescence. Red maple usually turns bright red in the autumn, ...

Biostimulators with chemical protection are a challenge in sustainable agriculture to obtain high yield, healthy, and pesticide-free wheat. The aim of this four-year spring wheat field experiment was assess the effectivity using herbicide, mixed fungicides protection, humic biostimulator. following treatments were tested: biostimulator (S), sulfosulfuron (H), H + S, propiconazole cyproconazole/...