oo a. ae 
my zy 
young as far as their ability to winter is concerned, and that a few 
days to 5 to 4 weeks is not of measurable importance when the bees have 
eepossible life of 6 to 8 months," 
FRUIT AND SHADE TREE INSECTS 
Effect of snow on California red scale.—-H. R. Yust, Whittier, 
Calif., reports a unique opportunity for observation of Chrysomphalus 
aurantii Mask. afforded by an unusual snowfall which occurred in cer- 
tain lemon groves near the Whittier laboratory. A light snowfall oc-— 
curred near Corona on December 12. On December 20 mortality counts 
were made of the scales on 16 lemons. Mr. Yust states: "The scales 
located on the top surface of the lemons where the snow settled showed 
a definitely lower survival in both resistant and nonresistant stages 
than those located on the under surface. The stages resistant to cya-— 
nide also seem to be more able to resist the cold weather than are the 
nonresistant stages. The survival of the resistant stages averaged 
29.9 per cent, whereas of the nonresistant stages, 10.4 per cent sur-— 
Vived exposure to the snow." (This has a very interesting bearing on 
the theory that "resistance" to cyanide gas is acquired!--C. L. M.) 
Finer sulphurs more effective in control of citrus thrips.--In con- 
nection with various studies of sulphur dust at the Lindsay, Calif., 
laboratory, E. A. McGregor makes the following report on the relation 
between fineness of division and insecticidal effectiveness. A sulphur 
company was induced to prepare three different "grinds" of sulphur, one 
of 200~mesh, one of 325~-mesh and one of 400-mesh. Each of these sulphur 
grades was replicated twice in a 16~acre orange orchard, and estimates of 
damage by citrus thrips (Scirtothrips citri Moulton) were made in each plat 
at harvest time. A very pronounced correlation between sulphur fineness and 
thrips control is indicated by data from this experiment, as follows: The 
area tested with 400-mesh sulphur showed 4.3 per cent damaged fruit; that 
treated with 325-mesh sulphur, 9.8 per cent; that with 200-mesh sulphur, 
15.1 per cent; and the untreated area, 48.1 per cent. 
Trichogramna may breed through winter in Georgia.-—-In a further ef- 
fort to learn more about winter hosts of Trichogramma minutum Riley, 
Herbert Spencer, in charge of pecan insect parasite work, reports that 10 
bait traps have been run in a large commercial planting 4 miles south of 
feetvany, Ga. "In all, 4,625 moths. were’ caught. in» the» jars during the 
month. At least a dozen species of cutworms were taken, numerous indi- 
dividuals of 4 species of cutworm moths laid their eggs when placed in 
cotton—plugged shell.vials and these eggs hatched normally, indicating 
that oviposition by these species during the winter is not unusual. 
The results of the bait-trap work confirm last year's results and give 
more weight to our theory that Trichogramma goes through our winter in 
the pecan groves by breeding in eggs of moths normally present there." 
