Viticulture Day Doesn’t
Leave Any Part of the
Vineyard Unturned
Leave Any Part of the
Vineyard Unturned
Managing Editor
Mechanical devices used to maintain vineyards were an additional focus of the day. Field demonstrations of sprayers were featured, along with presentations on mechanical pruning of grapevines, along with mechanical hilling up/taking down of soil at the base of the vine.
Canopy management is an emphasis of the work done at SWMREC. See the accompanying story by station director Tom Zabadal comparing five major trellising systems. Other work covered included inputs, Integrated Crop Management, insect control and diseases.
Two diseases of particular importance at SWMREC, phomopsis cane and leaf spot and tobacco/tomato ringspot virus (TSRV), were explained by Annemiek Schilder, Michigan State University’s small fruit pathologist.
The virus is transmitted by the dagger nematode, through grape and weed seeds and by infected plant material. It can be controlled by using virus-free planting material, planting resistant cultivars and rootstocks, thoroughly working vineyard soil one year before planting, keeping soil weed free and removing infected plants.
Phomopsis is a fungus dispersed by rain and irrigation water. Most of the spores are released in spring and early summer. Control options include use of disease-free planting material, judicious pruning and protectant fungicides such as Mancozeb and Captan.
Both diseases have been seen at SWMREC, said Schilder. “With phomopsis, the trick is to know when it is active and when the spores are dispersed,” she said. One of her research goals is to use spore taps to help determine the highest spore activity and thus time sprays better.
MSU’s small fruit entomologist, Rufus Isaac, described the first year of a screening program for new IR-4 minor crop insecticides on grapes. Initial research is focusing on grape berry moth, grape leafhopper, Japanese beetle and rose chafer. Insecticides from several new classes were tested on these pests, including neo-nicotinoids, oxidiazines, insect growth regulators, azadiractins and kaolin clay (Surround).
First-year results indicate promise using neo-nicotinoids Provado and Actara, the azadiractin Neemix and Surround against Japanese beetle and rose chafer. The insect growth regulators Esteem and Confirm show promise against grape berry moth as does the oxidiazine Avaunt. Actara, Esteen and Surround have potential against grape leafhopper.
A technique used by grape growers to prevent winter damage to the graft union involves hilling soil up around the base of the vine. During the following spring, this soil is taken down away from the vine. Gary VanEe of MSU’s Department of Agricultural Engineering has been heading a team working on better mechanical means of accomplishing these tasks.
The taking away of the soil has been more difficult than the piling up. VanEe made several adjustments to a commercial Weed Badger unit, and the new machine has performed well in trials. It has more power than prior units and is more easily placed by the tractor driver.
Two options are used to remove the soil. The first is the operator’s choice of brushes of varying thicknesses and the second a thicker metal paddle called a scalp disk. The paddle is designed for use on heavier soils, but it is more difficult to use than the brushes, said VanEe.
“It’s one of those dangerous machines. It will do what you want it to, but you have to be smart enough,” he said. “Moving soil is not that fancy of a job – it just has to be done right. It’s a finesse job.”
Trials continue for a new pre-emergent herbicide called Milestone, according to Mick Holm, DuPont technical representative. The label is still pending from the Environmental Protection Agency, but Holm believes the company will learn more information in September.
Milestone is a broad spectrum grass and broadleaf control which gives residual control of most annual grass and broadleaf weeds. It can be used on vineyards that are at least the two-leaf stage of growth. Fall or spring applications may be made at five to 15 ounces per acre.
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