Grape vines are not often subject to attacks by scale insects so there is seldom need for a spraying with strong lime-sulphur before growth starts.
Do not use the dilute lime-sulphur at any time for grape spraying. It stunts or checks the growth of the berries. Use the Bordeaux mixture.
DOWNY MILDEW commonly called “Red Grape” was very destructive last season and caused large financial losses to growers who did not spray.
BLACK ROT has been a serious disease in recent seasons. Growers cannot afford to risk the loss it may cause by neglecting to spray.
These diseases and others will be prevented very largely by spraying as follows :
WHEN THE SHOOTS ARE ABOUT S TO 10 INCHES LONG, Spray with Bordeaux mixture for black rot and downy mildew.
JUST BEFORE BLOOMING spray again with Bordeaux mixture for black rot and downy mildew and to every 50 gallons of Bordeaux, add 2 or 3 pounds of arsenate of lead to poison the grape-berry moth, and the rose-chafer. If this latter is serious use stronger poison even up to 5 lbs. to 50 gallons. A pint of the cheapest molasses added may help.
JUST As THE Blossoms ARE FALLING, make another spraying like the above.
ABOUT 10 DAYS OR Two WEEKS LATER, it may be necessary to make.
another spraying like the two previous, but this will depend upon the weather conditions and the amount of rot and mildew prevalent. If later sprayings are thought to be necessary, some material should be used that will not stain the fruit such as weak copper sulphate solution.
There are several grape insects that are found only in occasional vine-yards and then not every year. The grower should keep a sharp watch of his vines for them and if found, take prompt measures to destroy them. (If not familiar with their appearance send specimens to The Entomologist, East Lansing, Michigan.)
Those most likely to be found are the following:
FLEA-BEETLES may appear at any time but are most likely to come as the buds open in early spring. Spray with Bordeaux mixture and a strong poison, 3 or 4 pounds of arsenate of lead to every fifty gallons of the Bordeaux; if early in spring. Later use less poison.
In vineyards where the grape-berry moth is serious, spray with Bordeaux and an arsenical poison during the middle of July, before the 20th.
For, leaf-hoppers, sometimes incorrectly called “Thrip,” spray with nicotine or with kerosene-emulsion while the insects are young, and before they can fly. Later in the fall, clean up all rubbish and burn after cold weather sets in.
For climbing cut-worms, use cotton bands or bands of sticky mixture. On tender growth these can be put on strips of paper.