The red spider is not always red. He sometimes wears a brown coat, sometimes a brick-colored one. But his methods of operation are always the same. It is an easy matter to discover him after one knows what to look for. If the leaves of your plants begin to turn yellow, and to fall off, and they take on an appearance of general ill-health, suspect the spider as being at the bottom of the trouble. It is true that other causes may produce similar effects, but it is well to presume that the spider is responsible for the trouble, and an immediate examination should be made with a view to determining the facts in the case. Look at the underside of the yellowing and dropping leaves. If you find tiny webs there you can be sure that the spider is causing all the mischief. But do not be satisfied with this. Look sharply into these webs, and the chances are that you will see mites, red, brown, or brick-colored, scurrying about,-creatures so small that they look like grains of cayenne pepper more than anything else, when they happen to be red,- and then you will know that you have located one of the most destructive of all insects that work on house-plants. It hardly seems possible that so tiny a creature can do such deadly harm, but it will ruin the strongest of plants in a short time if allowed to go on with its work unchecked.
Fortunately, perhaps, we have but one remedy for the red spider, therefore we do not have to perplex ourselves in making choice among many. This remedy is water-clear water-applied in the form of a spray, or as a dip-bath. Above everything else the spider abhors moisture. He finds the atmosphere of our living-rooms so deficient in it that it is exactly to his liking. This explains why he locates himself on our house-plants. If, by any means, we can make the place unpleasant to him, he will either leave or be so discouraged by the unfavorable conditions we have created that he will do but little harm. In other words, if he cannot be completely routed, he can be kept in check. But, all the time, aggressive measures must be kept upon your part.
If plants have become badly infested before the presence of the spider is suspected, I would advise resorting to what may be called heroic treatment, and this at once, in order to cripple the enemy at the very outset of the campaign. Heat a tub of water to 120° F. and immerse the plants in it, allowing them to remain submerged about half a minute. It may seem to you, if you dip your hand in water heated to the point named, that a bath in it must mean sure death to your plants. But comparatively tender ones will not be injured by it, as you can easily satisfy yourself by experimenting with one or two before proceeding to treat all of them. The reason for using the hot bath is this: The spiders are on your plants, in great numbers. Spraying might not reach all of them, and it is desirable to get rid of them as soon as possible. The hot water will enable you to accomplish this. After having killed them off, the spray can be made use of, regularly, to keep them from returning, or, at least, to keep them in check. Apply water freely, and as often as possible. Most persons will probably think once a day too often, but it is not. Those who have a plant-room can use water recklessly, but quite likely those who grow their plants in the living-room will not spray oftener than two or three times a week. If they are not willing to go to much trouble in caring for them, they must be satisfied with inferior plants, such as they will always have if they do not give the amount of care necessary to secure best results. The more water you use in spray and shower the greater will be the amount of moisture in the air; the more moisture there is the fewer spiders there will be. Therefore use a good deal.
Do not be satisfied with spraying and showering. Keep it evaporating in pans on stove, and register, and radiator. This method of supplying moisture is an important one, because, if the pans are kept filled, there will be constant evaporation, while the result of spraying or showering, though apparently more effective at the time of application, is really much less permanent in effect.
Where but few plants are grown the dip-bath is always to be advised, because it never allows any part of the plant to escape a wetting.
In spraying your plants, it is well to turn them down on their sides, and throw the water up against the underside of the foliage, for there is where the spider lurks, thinking, no doubt, that he is safer there than elsewhere from dews and showers, which is what a spraying stands for to him it is reasonable to suppose. You will find the red spider doing just as deadly work among your outdoor plants, in a hot, dry season, as among your house-plants. But let a rainy spell come on and it is the end of him, for the time. This goes to prove that the proper way to fight him is to make it moist for him, and keep it so. Do not labor under the impression that he will leave of his own free will, for he never does that. He will only leave because you make it unpleasant for him, and the chances are even then that he will leave some of his posterity behind to wait and watch for the moment when you relax your vigilance. That moment the enemy will make an effort to reinstate himself. It is therefore highly important that the grower of house-plants should understand that eternal vigilance is the price of freedom from the red spider.
Scale attacks all plants having smooth, firm-textured foliage and stalks. You will find it in great quantities on Palms, along the lower side of the midrib of the leaves and the leaflet divisions, generally small flat, and wmite, with a dry look. A scaly look exactly expresses its appearance. On Lemons, and Oleanders, whose leaves are thicker and have more substance than those of the Palm, scale is often as large as a kernel of rice, with a rounded, shining upper surface, gray-green in color, and suggestive of pulpiness inside its shell. On other plants it takes on a dry, dark brown look. All varieties of scale affect plants in the same way-by sucking their juices. They affix themselves to the plant, and remain there indefinitely. It is to be supposed that they move sometime during their lives, but I have never yet seen one in motion. They cannot be removed by brushing, so firmly do they adhere to leaf or stalk. Spraying does not affect them. Dusting with powders is of no benefit. I know of but one effective weapon with which to fight this enemy, and that is an emulsion composed of half a pound of laundry soap, one teacupful of kerosene. Cut up the soap and pour over it enough water to cover it. Set it on the stove to become liquid. When dissolved, bring it to the boiling point and add the kerosene. Remove it from the stove and agitate it forcibly while cooling. A Dover egg-beater is one of the best things you can use for this purpose. The soap and oil will unite and form a jelly-like mass. Use one part of this mixture to ten parts water. The emulsion will readily unite with water, if well stirred for a minute or two before using. Apply this to the plant in a spray, using it liberally, or wash the plant with it, using a soft cloth or brush. After the first application has had a chance to soak in among the colonies of scale, go over the plant with a rather stiff bristle-brush and forcibly remove every creature that has loosened its hold, under the influence of its recent bath. Frequent use of the kerosene emulsion will prevent scale from forming in large quantities.
The woolly aphis, or mealy-bug, is a most disgusting looking creature when seen outside the cottony envelope in which he shuts himself. It is not often that he emerges from it, during the day, therefore it is generally supposed that the insect and its covering are part and parcel of each other. Such is not the case, however. The woolly or cottony substance is the home in which he hides the greater part of the time. When this pest congregates in a mass, as it has a habit of doing, it can be easily killed by pressure if one is not too squeamish to deal directly with it.
Like the scale, the mealy-bug subsists on the juice of the plant, and if allowed to increase its progeny will soon take entire possession of it, and the result is speedy death. There are several effective remedies in the market. Fir-tree-oil soap, lemon oil, and thrip juice, are all good, if used according to the directions which accompany them. They, like Nicotocide, can be procured of most florists, and all dealers in plants and seeds.
The eggs of the woolly aphis or mealy-bug are generally deposited in places where they are not readily discoverable, therefore it is necessary to fight this pest with liquids that will penetrate to all parts of the plant.
If any plant becomes badly infested before you find it out, I would advise destroying it at once, before the rest of your collection becomes contaminated.
It should be borne in mind that all insecticides are always to be applied to the plant itself-never to its roots, as some suppose.