312 



The blister beetles of America, for example, feed as larvae on locust 

 eggs, while in the adult stage they attack lucerne and often cause serious; 

 injury. Destructive methods of control include natural enemies,, 

 trapping, collecting, exposure to extremes of temperature, inundation,, 

 and the application of poisons, corrosive mixtures or fumigants. 

 Preventive measures include the application of dust sprays, formation 

 of ditches, fertilisation of poor soils, cultivation of resistant stocks, use 

 of screens, tarred bands, etc. Sporadic outbreaks are usually caused 

 by a sudden decrease in the number of natural enemies. Absolute 

 ])ird protection, unless it is proved that certain birds are more injurious; 

 than beneficial, is one of the best insecticidal methods. Too much 

 reliance should not be placed on methods of controlling widespread 

 pests by introduced parasites. When the prevalence of a pest is due 

 to the change of conditions brought about by man, complete relief lies; 

 only in the re-establishment of the balance of nature. 



Ferold (A. I.). Viticulture in South Africa. — Internat. Rev. Set. <&■ 

 Pract. Agric, Rome, vii, no. 1, January 1916, pp. 1-30, 

 [Received 2nd May 1916.] 



The principal insect pests of the vine in South iVfrica are Phylloxera, 

 calanders [sic] and mealy bug. Phylloxera made its appearance at the 

 Cape about 25 years ago, with the result that almost all the old vines 

 are now extinct and nearly 90 per cent, of the present plants are grafted 

 on American stocks. Nematodes cause considerable damage in very 

 sandy soils, especially to European stocks. Calanders are most trouble- 

 some in yomig plantations where the soil has been recently trenched, 

 especially in clay and peat soils. They cut the young leaves and shoots- 

 and later eat both berries and stalks of the green grapes ; they generally 

 disappear when the grapes begin to ripen, probably owing to the 

 excessive heat. The simplest way of getting rid of these insects is tO' 

 remove the soil around the vine so as to make a little hollow at the root 

 at the beginning of the rainy season ; w^hen this is done, they disappear 

 in about two years. Spraying with lead arsenate in spring and summer 

 is also effective. Mealy bug {Pseudococcus) does a good deal of damage 

 to trellised vines in the Cape Peninsula and the surrounding country. 

 Cyanide fumigation is the best remedy, though costly. 



Seitner ( — .). Bomhyx pini injurious to Pine Trees in Austria. — 

 Internat. Rev. Sci. & Pract. Agric, Rome, vii, no. 1. January 1916, 

 pp. 173-175. [Abstract from Centralblatt fiir das gesamte 

 Forstivesen, Vienna, xli, nos. 5-6, 1915, pp. 161-173.] [Received 

 2nd May 1916.] 



The extensive damage caused in 1913 by Dendrolimus {Bomhyx) pini 

 to a forest near Vienna has afforded the author an opportunity of 

 describing the hfe-history of this insect. The forest consists principally 

 of black pine, which is felled every 80 years and replaced by new 

 plantations. It also contains oaks, hornbeams and elms, and is 

 surrounded by large cultivated fields. In November 1912, a great 

 number of old cocoons were found in the bark of the pines and in the 

 hedges, and later large numbers of small winter caterpillars were 

 collected. Black pine, owing to the rough character of its bark, 

 appears to be more favoured than white pine by the hibernating 



