Mealy Bug

We have tried various emulsions of kerosene oil for this pest but with indifferent results. Alcohol, which is the basis of most insecticides for mealy bug, will do the work, but it is too expensive for general use. The imported preparation known as "Fir-tree Oil" is by far the best and most economical remedy we have yet tried. It kills the bug and its eggs and does no practical injury to the plants. In using the Firtree Oil or any similar insecticide, it is better, when practicable, to dip the plants in the preparation. In my experience one dipping is as good as ten syringings and much more economical. A common error in the use of all insecticides is the want of persistence in their use. It is much better to use a weak application of any insecticide frequently than a stronger dose of it at less frequent periods. For example, we have always found it more effective and safe to fumigate with tobacco smoke our houses twice a week lightly, rather than once a week and more heavily.

Rose Bug

This most dangerous insect first appeared in quantity about New York seven or eight years ago, and probably you are all familiar enough with it by this time. It is about as large as a lady bug, but is brown in color. The perfect bug feeds on the tops, eating the leaves and doing some injury, but the great mischief is done by the larvae feeding on the roots. This is a white grub about 1/4 in. long which is hatched in the soil by the bug. Its presence at the roots is quickly shown by the yellowing and dropping of the leaves, which by the inexperienced, may be attributed to the ordinary causes of over-watering or too high a temperature, but if a plant is dug up dozens of the grub will be found about the roots. The only remedy seems to be to pick the perfect bugs from the tops by hand. The Rose bug has not done so much damage in the last few years, as the now general practice of planting new stock each year seems to have disturbed and prevented their breeding.

Black Ants

These symbols of industry will cause considerable injury and annoyance in a greenhouse if allowed to gain headway. They tunnel the soil in pots and benches, and carry the soil up the stems of the plants, and encrust with it the mealy bug and scale, which they pretend to devour but never diminish. They can be readily exterminated by dusting the large runs of them with Pyrethrum, applied with a bellows. It is useless to spread it around by hand, as they are killed by breathing it, and it must be distributed in fine particles. In the winter of 1883 our place became badly infested with ants, and only the persistent daily use of Pyrethrum for three months exterminated them.

Mildew

The only remedy we have ever used for mildew is sulphur, either by putting it on the pipes so that the fumes will be thrown off by the heat, or in the liquid form as follows : 1 lb. lime and 1 lb. sulphur in 2 gals, water; boil this down to one gallon, and use a wineglassful of this to 5 gals, of water, and syringe the affected plants twice a week. This is particularly useful in summer when not firing, and is a certain remedy. It has been recently suggested to use linseed oil mixed with sulphur for painting the pipes, it being claimed that in this way the sulphur would do no harm to the plants. Now, while the linseed oil may be a good thing to mix with the sulphur to make it stick to the pipes, it is certainly of no other benefit. It is well known that sulphur mixed with water alone is used on hot water pipes in greenhouses and graperies, as an antidote against mildew and red spider, without injury to the plants. It has been our practice for years to sprinkle the pipes with water and then dust the sulphur on while wet, and I have never seen the slightest injury to roses or other plants by this manner of applying it.

Many serious results have occurred by burning sulphur in greenhouses or applying it on brick flues, where the temperature is perhaps 3000, but I never heard of injury to plants resulting from its being applied on hot water pipes where the temperature is usually under 2000.

Black Mildew Or "Black Spot"

I have had scarcely any experience with this, as we never have had it on our place, except in a slight degree on some hybrid Tea roses. I have noticed, however, that it is most prevalent in rose establishments where the stock is grown for propagation, in shallow benches, in soil without manure. It is almost unknown where the plants are grown for cut-flowers, and consequently are liberally fed. In all probability this continued starving leaves the stock in such condition that it invites the "black spot." There is a formula which is said to check it, but it has been kept a secret by the discoverer.

In conclusion, I would say that, in my opinion, the ventilation of a greenhouse has more to do with the health of its contents than any other one cause. This is particularly true with roses. If air is given on a rosehouse, day and night during July and August, there will be little trouble with mildew, as the cool night air and the action of the wind all tend to toughen the fibre of the wood and leaves and give strength of constitution to the whole plant, so that when the spores of mildew and other fungoid diseases strike, they do not take root, but glance off harmlessly from the hardened and fortified foliage. Jersey City Heights.

[Read before the American Society of Florists. - Ed. G. M].