Chrysanthemums are troubled with several of our insect pests. The daily syringing which should be done every bright morning will effectually keep down the red spider. Thrips we are very seldom troubled with. Syringing must also prevent the appearance of these worst of creatures, and if not the nicotine does. The commonest but easiest to combat is the green and black aphis. A weekly fumigating by burning tobacco dust will effectually keep them down. Where it may be inconvenient to fumigate the nicotine sprayed over the plants with a knapsack bellows will thoroughly clean the plants or aphis. It is diluted something like 400 to one and it does not stain in the slightest, either the leaf or flower.
Mildew troubles some varieties, notably that splendid old yellow Golden Wedding. It appears a draught is the cause of it. We noticed only last winter that seven or eight feet of a bench near a door that was continually open was attacked with mildew, while beyond the influence of the draught it disappeared. If late in the season, say October, the mildew appears, and you can occasionally fire up, then some flour of sulphur, mixed with linseed oil, till it is about like paste and patches of it smeared on a pipe at intervals of every three or four feet is the best remedy for it. If you cannot fire up then the flour of sulphur must be lightly scattered over the leaves, but this is not nearly as effective as putting it on the pipes. The majority of blooms are cut without the aid of any fire heat, but often towards the end of October and during November a little fire heat is necessary, not only for a frosty night, but for cool, rainy weather, when the dampness will settle on the plants and unless quickly dispelled will rot and spot the petals. A dry atmosphere must be maintained with all open flowers.
When the plants are growing fast and we should get a few days dull, moist weather, growth will be very soft and on the return of a very bright, sunny day the tender tips will wilt and scald. Look out for this and spray frequently to keep the atmosphere moist, or a temporary shade may be applied, and for this purpose there is nothing so quickly applied as clay and water, and if a shower does not take it off in a day or two the hose soon will.
There is a brown, hairy caterpillar, some one to two inches long, that is very troublesome just about the time the buds are opening. The plants must be looked over frequently for these caterpillars. They will be found on the underside of the leaf and if let alone they will destroy many a fine bud. We know no way but hand picking to destroy them.
Grasshoppers seldom bother us, yet we have seen seasons in rural districts when chrysanthemums would have been stripped of leaves and buds, but we wore not growing "mums" in that neighborhood. To put some kind of netting over the ventilating spaces would have been our only salvation.
Exhibition Vase of 100 Timothy Eaton.
Of all the discouraging diseases we have to fight, the rust is the worst. It is a fungus and quickly spreads. The underside of the leaf has a varnished appearance and the sides of the leaf begin to curl under. When pressing the two sides together the leaf does not bend but cracks. If badly affected the flower is worthless. It does not usually appear till middle or late in September, when we get cool nights, and is encouraged by dampness. We have again noticed that it usually begins near a door. That dampness or stagnant water lying around on the floor is a fruitful cause of it we have had ample proof years ago. There is a good deal of difference between the moisture created by a spraying in a well drained and well ventilated house and the dampness of a poorly drained and poorly ventilated one. Some varieties can resist this rust much better than others, but if it once gets a good foothold and conditions are favorable for its spreading, any variety will succumb. Bordeaux mixture is the usual remedy, and if you think the conditions in your house are favorable for the appearance of rust begin when the plants are small and spray with Bordeaux or ammoniacal mixture every two weeks. With a dry, well drained house, no sharp draughts, plenty of ventilation and no moisture on the foliage during night, you will not likely see any rust.
Chrysanthemums want no shade, even in our hottest months, and the yellow and white varieties want none at any time, but the red and pink fade under bright sun and should, to retain their bright colors, have a slight shade as soon as the buds begin to open. A light shade of naphtha and white lead will do for this. It can be syringed on, but can be put on much better with a whitewash brush with a long handle.