Several species of the predatory mite family Phytoseiidae are of major economic importance for biological pest control in crops, including grapevines. Plant diversification in agrosystems is reported to enhance useful biodiversity and provide ecosystem services. Thus, agroforestry, which consists in co-planting trees and crops, is assumed to be a possible way to ensure regulation of pest outbre...

A simplified grape carbon balance model, called VitiSim, was adapted from the simplified apple carbon balance model developed earlier. The model uses a daily time step, a big-leaf daily canopy photosynthesis light response and respiration of organs based on mass and specific respiration rates. Weather inputs are only daily max and min temperatures and radiation. Partitioning is based on the bal...

High copper (Cu) levels in uprooted old vineyard soils may cause toxicity in transplanted young vines, although such toxicity may be reduced by inoculating plants with arbuscular mycorrhizal fungi (AMF). The objective of this study was to evaluate the effects of AMF on the plant growth, chlorophyll contents, mycorrhizal colonization, and Cu and phosphorus (P) absorption in young vines cultivate...

Vascular occlusions are common structural modifications made by many plant species in response to pathogen infection. However, the functional role(s) of occlusions in host plant disease resistance/susceptibility remains controversial. This study focuses on vascular occlusions that form in stem secondary xylem of grapevines (Vitis vinifera) infected with Pierce's disease (PD) and the impact of o...

Partial correlation vines and the onion method are presented for generating random correlation matrices. As a special case, a uniform distribution over the set of d× d positive definite correlation matrices obtains. Byproducts are: (a) For a uniform distribution over the space of d × d correlation matrices, the marginal distribution of each correlation is Beta(d/2, d/2) on (−1, 1). (b) An ident...

Both in classical multivariate analysis and in modern copula modeling, correlation matrices are a central concept of dependence modeling using multivariate normal distributions and copulas. Since the number of correlation parameters quadratically increases with the number of variables, parsimonious parameterizations of large correlation matrices in terms of O(d) parameters are important. While ...

A crucial practice for vineyard managers is to control the amount of fruit hanging on their vines to reach yield and quality goals. Current vine manipulation methods to adjust level of fruit are inaccurate and ineffective because they are often not performed according to quantitative yield information. Even when yield predictions are available they are inaccurate and spatially coarse because th...

Vineyards were surveyed for grapevine leafroll-associated viruses and their insect vectors in New York State's Finger Lakes region in 2006-2008. Grape mealybug, Pseudococcus maritimus (Erhorn) (Hemiptera: Pseudococcidae), European Fruit Lecanium, Parthenolecanium corni (Bouche), and Cottony Maple Scale, Pulvinaria acericola (Walsh and Riley) (Hemiptera: Coccidae) were identified as vector speci...