The lecturer on horticultural subjects soon finds that the joint in his armour which is tested the most frequently is that bearing on his knowledge of the enemies of crops, and the means of extirpating them. He may be able to describe in minutest detail every phase in the great art of making a hole with a crowbar to grow a big Carrot, but unless he is able to present an anxious inquirer with an infallible remedy for getting rid of the Carrot's natural enemy, he will be regarded as found wanting.
Of course, the lecturer discovers this sooner or later, and then proceeds to distribute recipes broadcast. He has been doing this for some years now, and the same thing was done by horticultural editors in years gone by; but there seem to be just as many wails over the depredations of plant pests as ever there were. Either the recipes are not what they ought to be, or else the anxious inquirer forgets all about them when the time comes to put the information to the test.
There may be some vegetables that are not attacked by injurious fungi or insects, but they are very few. I have never known Artichokes affected during all the years that I have grown them, and the same may be said of Leeks. On the other hand, Potatoes, Cabbages and other Greens, Onions, Carrots, Celery, Parsnips, Beetroot, Peas, Beans, Cucumbers, Salsify, Tomatoes, and Turnips are all troubled.
In offering a few hints on the subject of combating vegetable enemies, it may be convenient if I take the several crops alphabetically.
Grubs of a slaty colour, and about 1/3 inch long, may often be seen infesting Asparagus shoots in summer. They come from the eggs of a bluish black beetle named Crioceris Asparagi, and often do much damage. Prepare the following mixture, and dip the infested shoots in it, afterwards syringing with clear water:-
1/2 lb. soft soap. 1/4 lb. flowers of sulphur. 1/4 lb. soot.
Mix well in a pail of warm water.
Parsnips are sometimes attacked in the foliage similarly to Celery, and the same remedies may be applied. But they are more commonly troubled by canker, which causes foul blotches on the roots. I have already said that this is due to overmanuring. The remedy is a dressing of lime at the rate of 2 lb. per square yard.
After growing Salsify without trouble for several years, I was harassed by a fungoid disease in 1901. It formed small whitish pustules on the leaves, which were almost covered. Wishing to observe its progress and results, I made no attack on it. The plants appeared to grow out of the disease late in the summer, but the roots never developed to their proper proportions. At the first trace of it in future, I shall try the Bordeaux Mixture.