INSECTS INJURIOUS IN THE FLOWER-GARDEN. 



823 



ficient depth of shade if secondary or neutral 

 ones. Much of the success of these operations 

 will depend on the state of the weather ; 

 that which is cloudy and moist being the 

 best, a bright scorching sun or evaporating 

 wind being the worst. The state of the soil is 

 in the hands of the operator ; and we need 

 hardly remark that it should be moist from 

 rain, or rendered so artificially, not only where 

 the plants are to be set, but also where they 

 are to be taken from, and as little dependence 

 placed on shading as possible ; nevertheless, in 

 some cases this will be found necessary. 



§ 10. INSECTS INJURIOUS IN THE 

 PLANT -HOUSES AND FLOWER - GAR- 

 DEN. 



In noticing the insects most injurious to 

 plants in plant-houses and flower-gardens, we 

 have deviated from the course followed in the 

 culinary and fruit gardens, where the insects 

 peculiar to each plant and tree are noticed 

 under the head of the plant or tree upon which 

 they are found. In the case of plant-houses and 

 flower-gardens, many species of plants are in- 

 fested with the same species of insect, and 

 therefore, to prevent repetition, we have placed 

 the insects most injurious to these departments 

 in a section by themselves. 



We have noticed those that are most destruc- 

 tive ; and although, in some cases, the descrip- 

 tions are brief, we trust they will be such as 

 will enable the cultivator to determine the 

 genera and species of his insect enemies, while 

 our notices of their habits will enable him to 

 wage a more successful warfare against them. 

 To have even enumerated every species of insect 

 which exists in our gardens, far less to have 

 given a detailed description of them, would have 

 far exceeded our limits, and indeed have been 

 of little practical advantage to the cultivator. 

 We may further remark that whatever directions 

 may be laid down for the suppression of insects, 

 unless these are followed up with energy and 

 unremitting perseverance until the end is ac- 

 complished, all superficial attempts will only be 

 time and labour lost. 



The mealy bug (Coccus adonidum Linn.) is a 

 sad pest in tropical-plant houses, some plants 

 being exceedingly liable to be attacked by them, 

 while others are comparatively seldom visited. 

 We have noticed this insect, p. 639 ; — to what has 

 been there said regarding it, we may add that 

 frequent syringing with pure water applied with 

 force, and keeping up a very high and humid 

 atmosphere, is believed to be the best wholesale 

 mode of destroying them. Such plants as 

 Coffea, Musa, Canna, Hoya, Alpina, Stephanotus, 

 &c. are most subject to them (vide p. 661). Of 

 the Coccus family, Ruricola, in "Gardeners' 

 Chronicle," speaks in the following terms : — 

 " The scale insects vary so considerably in their 

 habits that they may with great propriety be 

 divided into three sections, which will form as 

 many genera. 1st, There is the true or tropical 

 coccus, the female of which is covered with a 



scale inseparable from the animal, — familiar 

 examples are the C. hesperidum and C. vitex 

 of Linnaeus. 2d, A large number is distinguished 

 by Bouche, under the name of Aspidiotus, of 

 which C. nerii of that author and C. bromelise 

 are examples, — in this group the females are 

 covered with a scale which does not adhere to 

 the animal. 3d, Those species, comparatively 

 few in number, I believe, whose females are 

 not furnished with scales, but are merely 

 powdered over, — they are very different also 

 in not being stationary, but run about when 

 full grown as well as when young, of which 

 C. adonidum is the type." 



The oleander scale (stspidiotus nerii Bouche), 

 fig. 267, said to have been imported from 



Fig-. 267. 



OLEANDER SCALE. 



America, is found on most plants of this family. 

 The female is larger than the male, and appears 

 like a round flat shield, inclining to yellow, 

 almost destitute of legs ; it feeds on the leaves 

 by sucking the sap out of them with its rostrum. 

 The shield of the male is quite white, the per- 

 fect animal brownish yellow, with white wings. 

 Although called the oleander scale, it is found 

 on many other plants, both in the greenhouse 

 and stove. It is most difficult to suppress when 

 once it has been introduced into a collection. 

 One remedy is to cut the plant over by the sur- 

 face, and re-grow it again in a house or pit where 

 no scales have been admitted. Washing the 

 leaves and branches with soap and water is per- 

 haps the next only remedy. 



The orange scale (Coccus hesperidum Linn.) — 

 In form similar to the last ; in colour differing, 

 inasmuch as this appears as a nut-brown shield ; 

 equally abounding with the other, and in similar 

 situations attacking not only the orange tree, but 

 other trees also, the camellia in particular. The 

 same means of suppression must be used as in 

 the former case. 



