397 



with mean temperatures between 70° and 80° F., it lasted 4-5 

 days. The average length of the larval stage is 2-58 days, of the 

 first nymphal stage 2-8 and of the second 2-84. 



The length of the adult life also varies according to temperature and 

 possibly other conditions. The average duration of the life-cycle is 14 • 2 

 days, allowing 17 generations during the period of activity, which 

 extends for about 240 days, from the end of August to the beginning of 

 April, but this number is influenced by climatic conditions and other 

 factors interfering with the normal activities of these mites in the field. 

 Intermittent rains often interfere with the regularity of the generations. 

 Drenching and frequent rains may prevent the red spider from 

 becoming established on the trees during the summer in Florida. 



The predatory enemies of this pest are Scolothrips sexmaculatus, 

 Perg., feeding on larval and adult stages ; Chrysopa lateralis, Guer., 

 feeding on the larvae ; Scymnus utilis, Horn, the most important 

 enemy of the red spider, feeding on all its stages ; and 5. kinzeli, 

 Casey, and Leptothrips inali, Hinds, feeding on larvae and adults. 



Experiments with insecticides are described. After the fruit has 

 been picked, liquid lime-sulphur should be used during the winter 

 at the rate of 1 : 60, but if the temperature is above the normal and 

 the trees do not attain a thoroughly dormant condition, the spray should 

 be used at the rate of 1 : 75. For applications before the fruit is 

 picked 40 per cent, nicotine sulphate 1 : 900 with the addition of 

 2-3 lb. of fish-oil soap to every 100 U.S. gals, of diluted spray is 

 recommended. Sulphur dust was very effective in the experiment, 

 but could not be satisfactorily combined with the nicotine sulphate 

 so as to be a practical insecticide for general application. 



Simmons (P.). Controlling the Ham or Cheese Skipper. — Separate 

 from National Provisioner, Chicago, 29th April 1922, 2 pp. 



A brief account is given of the life-history of the cheese skipper 

 [Piophila casei, L.] [R.A.E., A, ii, 572]. 



At temperatures of 80° [F.l and higher, the feeding period of the 

 larva only lasts five days and growth is rapid. All stages are prolonged 

 at lowered temperatures. The minimum life cycle observed was 12 

 days from adult to adult. Under natural conditions the average is 

 probably two generations a month during the summer. The red- 

 legged ham beetle [Necrohia rufipes, DeG.], although a natural enemy of 

 this pest, cannot be relied on for its control as it is itself an undesirable 

 meat pest. Pachycrepoideus dubius, Ashm., may prove useful as a 

 parasite of the pupa. 



To prevent infestation all doors and windows should be fitted with 

 screens at least as fine as 30 meshes to the inch. Infested rooms can 

 be fumigated with sodium cyanide at the rate of one pound to 1,000 

 cubic feet for 24 hours. In tightly sealed rooms at a temperature 

 over 60° the unprotected larvae and pupae will also be killed. All 

 food should be removed before fumigation. 



The Tobacco Slug. — Rhodesia Agric. J I., Salisbury, xix, no. 2, April 

 1922, p. 130. 



Owing to the prevalence of Lenta bilineata, Germ., in the Union of 

 South Africa, the importation of tobacco leaf into Southern Rhodesia 

 from that territory, except under the authority of the Director of 



