3J9 



Mackie (D. B.). The Status of the Codling Moth in its Relation to the 

 Walnut Industry. — Mlhh/. Bull. Col. State Commiss. Hortic, 

 Sacramento, viii, no. 5, May 1919, pp. 250-256, 3 figs. 

 Infestation of walnuts by Cydia {Laspeyresia) pomonella (codling 

 moth) has so much increased recently that it appears probable that a 

 strain of this species has been developed which can complete its life- 

 cycle on walnut and finds that food-plant congenial. The damage 

 to this important crop in 1918 shows that the moth has potentialities 

 for developing into the most serious of walnut pests. It has, however, 

 been proved that it can be controlled both in the field and through the 

 channels of the trade, and that it is only necessary that concerted 

 action be taken by growers and dealers to prevent losses to future 

 crops. Development on walnuts is not yet fully understood, but the 

 methods of handling the crop in order to eliminate infestation are 

 fully dealt with. These include treatment of the sacks with live 

 steam, hot water, hot air and an electric mangle. [See also this Review, 

 Ser. A, vii, p. 317.] 



Armitage (H. M.). Controlling Mealybugs by the Use of their Natural 

 Enemies. — Mthly. Bull. Cat. State Commiss. Hortic., Sacramento, 

 viii, no. 5, May 1919, pp. 257-260. 



The species of citrus-feeding mealy-bugs that occur in Southern 

 California are Pseudococcus citri, Risso (citrus mealy-bug), P. gahani, 

 Green (citrophilus mealy-bug) and P. maritimus, Ehrh. ; to these has 

 been added during the last season P. kraunhiae, Kuw, (Japanese mealy- 

 bug), which as yet occurs only in one locality, where an attempt is 

 being made to eradicate it. There are many natural enemies of these 

 Coccids in California, but they have not all proved suitable for rearing 

 and distribution on a large scale. Sympherobius barberi and S. cali- 

 Jornicus (brown lace-wings) are both excellent winter and spring 

 predators, but are themselves highly parasitised, as is also Chrysopa 

 sp. (green lace-wing). The Coccinellid, Hyperaspis lateralis, another 

 native predator, is an efiective check on P. citri, but does not readUy 

 adapt itself to P. gahani. An Agromyzid fly, Leucopis bella, devours 

 many egg-masses, but the most promising enemy is apparently the 

 Coccinellid, Gryptolaemus montrouzieri, originally introduced from 

 Australia. The manner of rearing and distributing it is described. 

 Under natural conditions it is able rapidly to clear an infestation of 

 mealy-bugs from citrus orchards, but appears too late to protect the 

 tree. By having C. montrouzieri available for liberation in the spring 

 and distributing it in quantities that will give it an equal start with 

 the mealy-bug, the latter may increase for a short time but will not 

 become sufficiently numerous to injure the tree or crop. Dming the 

 past season 54,330 adults of C. montrouzieri were liberated on 95 

 properties infested with mealy-bugs, about 60 per cent, of these being 

 collected in the field and the rest in the insectary . In the present season 

 the equipment has been doubled and it is hoped that the figures wiU be 

 increased greatly during the coming year, with corresponding success. 

 *% Some attempt has also been made to rear Paraleptoinastix abnormis, 

 Gir., a small Hymenopterous parasite of Pseudococcus citri, which was 

 introduced from Sicily about 4 years ago. It is hoped to liberate 



