Grapes are one of the most rewarding fruit crops for home gardens. They stay manageable —they are easy to care for and harvest, and there is a good selection of varieties for nearly every climate.
They ordinarily thrive without much in the way of special sprays, but if it’s perfection you’re after, here are some “ground rules” for achieving it.
Choosing Good Grape Varieties
Perfection starts with good varieties. Grow kinds recommended by your state experiment station or extension service, choosing kinds resistant to diseases such as black rot, downy mildew, powdery mildew, and anthracnose.
Southern states choose resistance to Pierce’s disease. Nurserymen, county agents, or catalog descriptions will yield information on this point of disease resistance.
Good Cultural Methods
All troubles are minimized if you follow good cultural methods: The first growing season train shoots on a stake. Then, the second spring on, tie them to a two-wire trellis.
Each year prune and retie vines. Burn the prunings. Set plants 8’ to 10’ feet apart in rows and leave nine to 12’ feet between rows. Keep down weeds. Collect and burn leaves in the fall, and destroy rotting fruit. In early spring, cultivate to cover all dropped fruits and other plant debris with soil.
Be careful around grapes if you use weed killer on your grounds. Use only the amine form of 2,9-D at low pressure near grape plantings. Put this on your lawn only in fall when the wind moves away from the grapes
Always use a separate sprayer for weed killers—not the one you use for pesticides. Grape symptoms of 2,4-D injury may appear one to three weeks after exposure to fumes or spray drift and as far away as a mile or more.
An “average” spray program for home grapes is outlined here. Your county agent may advise something more specific for your area.
In most northern states, five or six sprays in a season are enough; in southeastern states or a long season, rainy areas, you may need eight to 12 sprays in a season.
What To Spray With
Use a multipurpose fruit spray that contains captan or verbal plus methoxychlor and malathion. Where downy mildew or powdery mildew are problems, add two tablespoons of a fixed copper fungicide to each gallon of spray.
Wet plants completely with each spray. Follow the precautions listed on the label. And start spraying in time. Little is accomplished if you wait until the fruit rotates or insect damage appears.
Specific Major Troubles
2,4-D injury. It may be found in most communities: deformed fan-shaped leaves, tendrils, leaves with sawtooth edges, and close yellow veins. Fruit ripens unevenly or not at all.
Control: Protect from 2,4-D injury as previously described.
Black Rot
Widespread east of the Rockies. Leaves develop small circular red-brown spots; tan spots appear on fruit and become sunken. Rotted areas enlarge and turn brown-black, and the berry fades and becomes a black “mummy.”
Control: resistant varieties; good culture; spray containing captan, zineb, verbatim, thiram, plan, or fixed copper.
Downy Mildew
Common in humid areas except for the south of Virginia. Green-yellow scars form on the upper leaf surface, later turning red-brown.
Dense, white, downy mold grows on the corresponding underleaf surface. Fruits and tendrils also attacked. As a result, leaves and fruit may drop early; new growth is stunted.
Control: resistant varieties, good culture; spraying when mildew is first seen with a spray containing zineb, fixed copper, or captan.
Other Fruit Rots
Widespread in rainy weather. Ripening fruit rots may be covered with mold; control resistant varieties; good culture; spray same as for black rot or downy mildew. Handle fruit sparingly.
Powdery Mildew
Serious in California and increasingly common in other places. Flour-like patches appear on leaves, tendrils, blooms, and young fruit; later, they may turn brown or black. Fruit may be dwarfed, russeted, cracked, or drop off before harvest.
Control: resistant varieties; good culture; spray with fixed copper or karathane at least twice.
44659 by Malcolm Shurtleff