If a proper degree of moisture is maintained and syringing properly done, red spider and thrips are seldom seen. If thrips are very persistent, then vaporize with tobacco several successive nights. Mealy bug is sometimes very troublesome and more often when the plants are crowded. If not removed by ordinary syringing, then have the plants brought to some nearby place, where water runs off quickly, and by laying the plant down and turning it on all sides with a sharp, strong stream they can be washed off clean.
Scale is the worst enemy we have to contend with, and the common brown scale is much easier removed than the white. I mention these two, for that is sufficient here, because the remedy would be the same were there twenty species of these insects on our palms; and there are not only twenty, but perhaps twenty hundred species known to entomologists. It appears they do not multiply with anything like the rapidity of the aphides. That is a consolation. And they breed and lay a crop of eggs but once a year. So if the palms are thoroughly cleaned, say in August, you should see no more of them for another six months. It is often supposed that they are without the power of locomotion, but when very young in the larval state they creep about till they find a comfortable spot, then insert their beak into the leaf or bark, and that is their residence for life. Entomologists say that the ants which feed on the excretion of the scales take the young insects and plant them on different parts of the leaves of palms and ferns. If this is so, then we should get rid of the ants.
There are several means of removing the scales by washing with some insecticide, and when you wash the leaves, see that every part is thoroughly cleaned. You can see the large scales, but the very small ones might elude you. Sponge with warm water, to which has been added two ounces of whale oil soap in two gallons of water.
A solution of two ounces of kerosene emulsion in five gallons of water is also used, and applied with a sponge.
Other methods are applying water to which has been added a hundredth of its bulk of nicotine extract, of a weak solution of fir tree oil; this also is recommended by some.
You cannot with any effect syringe these solutions on the plants. They must be sponged; and remember that the very young leaves will not endure as strong a mixture as the matured leaf, and the leaf stalks are uninjured by a still stronger solution.
The following appeared in a recent number of a horticultural journal, and is, I think, worth insertion here. The white scale we get from Europe on imported plants is certainly a very bad species, and although a free trader, I would put a very high tariff on him:
" The sending out of palms and ferns afflicted either with mealy bug or scale is much to be deplored, but the number of complaints that reach us from time to time Mould indicate that some houses continue to supply their customers with a quantity of live stock over and above what has been ordered, much to the detriment of the stock as well as the senders.
"The florist who would have clean stock must in the first place keep all his own plants perfectly free from these pests, and whenever a new consignment of plants is received take such measures with them as will insure their being thoroughly clean before introducing them among those already in his possession. As a preventive against introducing foreign-bred scale or mealy bug into houses, we would suggest the following method: If the plants are not more than two or three feet in height, have a suitable size vessel filled with lukewarm water to which has been added fir tree oil in the proportion of one-half pint to ten gallons of water. As the plants are unpacked and before they are potted dip them thoroughly overhead in the mixture (excepting the ball, of course), being sure to immerse the plant right down to the neck. Plants too large for this treatment may be sponged or syringed thoroughly with the same concoction. After this treatment pot them up, syringe with clear water, giving them an isolated position - quarantining them, so to speak-until one is satisfied that they are perfectly clean. If after a few days live scales are still observed and the plants are in too large numbers to go over them by hand, take five gallons of lukewarm water, add one-half pint of fir tree oil and syringe again; or make up a less quantity and sponge them with it. By treating infested plants when they first arrive, it will be found that the pests can be combated much easier than if the work is deferred, while at the same time the danger of the insects spreading to other stock is greatly minimized. "