FEBRUARY 22, liniO. 



The Weekly Florists' Review. 



345 



A Table of New Varieties at the Carnation Society's Exhibition at Buffalo last Thursday and Friday. 



they make short flights, which gives 

 them the appearance of hopping lilCe 

 the rose leaf hopper. The larvae or 

 immature thrips, both males and fe- 

 males, are wingless. They are of a 

 light yellow color, while the ailults 

 closely resemble the soil around the 

 plants. 



The adult females deposit their eggs 

 within the tissues of the plants upon 

 which they feed. The time required 

 for the eggs to hatch and the num- 

 ber of broods occurring each year is 

 not known. This in.sect probably hi- 

 bernates as adults and not in the egg 

 state. They hide away under rub- 

 bish and under the rough bark of the 

 plants on which they feed. 



They usually attack carnations in 

 the fall while the latter are in the 

 field. Feeding as they do on the ten- 

 der unfolding leaves of the plant, 

 they may, in some cases, cau-^e the 

 twisting that is called "carnation twit- 

 ter." The chances are that "carna- 

 tion twitter" can be produced by any 

 cause which checks the growth of the 

 plants, and is rarely the work of 

 thrips. 



' When the plants are transferred 

 from the held to the forcing-house 

 the thrips are taken along. As soon 

 as the plants commence to throw flow- 

 er buds the thrip will work its way 

 into the latter, where he will be safe 

 from all human attacks. Here it 

 feeds upon the partially developed 

 petals, not only distorting them but 

 robbing them of their coloring pig- 

 ment, so that the flowers not only 

 have irregular white blotches en the 

 petals, but often they do not open 

 properly. In some cases the petals 

 bleed to such an extent that flowers 

 rot before they open. ' Not satisfied 

 with making the flowers appear as if 

 affected with leprosy, they depos t 

 their eggs in the tissue of the inner 

 or upper surface of the calyx. 



Combating the Pests. 



P.cf(ue taking up the subject of con- 

 trolling the three pests discussed thus 

 far. we should know how they feed 

 and breathe, also how they g^t into 

 the forcing-house. 



The greenfly is provided with a pro- 

 boscis or beak-like mouth similar to 

 that of the bedluig. With this it punc- 

 tures the plants and sucks the clear 

 sap or liquid from all the surrounding 

 tissue. L'sually the tissues of the 

 plant are only slightly broken liy the 

 feeding process of the greenfly. The 

 red spider and the thrips are both pro- 

 vided with biting mouth parts. They 

 first bite open the cells of the leaf tis- 

 sue and then proceed to lap or suck 

 up not only the juices but also the 

 coloring matter from the broken cells. 

 These broken empty cells give the 

 whitish appearance to the plants on 

 which the latter pests feed. Hence, 

 the small size of these pests, combined 

 with their method of feeding, makes 

 the use of poisons impossible. 



All insects breathe by means of 

 small openings called spiricals, which 

 are arranged in rows on each side of 

 the body. The spiricals connect with 

 small tubes or arteries which divide 

 and penetrate to all parts of the in- 

 sect. Therefore, insects have air in- 

 stead of blood circulating to all parts 

 of their bodies. The closing of the 

 spiricals with powder, washes, or 

 with fumes of any kind suffocates the 

 insect, and this is the only way we 

 have of combating the above pests. 

 With such small insects this is easier 

 said than done. It is almost impos- 

 sible to make the treatment thorough 

 on such small objects. 



All three pest.s can be carried into 

 the forcing-house at the time the 

 plants are taken in. The greenfly and 

 thrips both produce winged individu- 

 als which can find their way into the 

 houses by way of the ventilators. Red 

 spider can be carried into the houses 

 on cannas, dahlias, or any other plants 



or bulbs which have some tops on 

 tliem when stored under the benches. 



The oft recommended remedy for 

 greenfly and thrips is fumigation with 

 tobacco or steam from tobacco ex- 

 tracts. Water is the standard remedy 

 for red spider, and is often assumed 

 to be good for thrips. I have yet to 

 find the forcing-house which has once 

 become infested with greenfly, and aft- 

 erward fumigated weekly with tobacco 

 in some form until it shows signs of 

 nicotine poisoning, in which I cannot 

 still find the greenfly hidden away in 

 out-of-the-way corners. I doubt if 

 ever an adult thrip was killed by fumi- 

 gation of any sort. Unless the latter 

 are very thick and crowded for feed- 

 ing ground, they are hidden away in 

 the folds of the leaves too well pro- 

 tected to be reached even by tobacco 

 smoke. Up to the present time we 

 have no safer method of controlling 

 the greenfly on carnations than fumi- 

 gation with tobacco smoke at time the 

 plants are flowering. 



Fuinigation with hydrocyanic acid 

 gas has been recommended for vio- 

 lets and in a few cases for carnations. 

 I have tested the latter in various 

 ways, making upward of fifty distinct 

 tests on carnations. Plants that are 

 flowering will be liable to be injured 

 from the banking of the gas in the 

 upper portions of the house. This gas 

 is so much lighter than air and com- 

 presses itself into the upper spaces of 

 the house to such an extent that, even 

 though only one-half ounce of 98 per 

 cent cyanide of potash was used for 

 eviry " 1.000 cubic feet, it banked 

 enough to cause serious injury. The 

 injury was not noticeable until about 

 two weeks after treatment, and con- 

 sisted of a whitened ring around the 

 buds and a few white spots on the 

 upper leaves. The former did not ap- 

 pear to interfere with the perfect de- 

 velopment of the flowers. In the absve 

 case, where only one-half ounce of the 

 cyanide of potash was used, the gas 



