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Study of Temperature Factor in Flooding for the Control of x 
a “Wireworns ‘(Linonius californicus Mann.) 
Bo W. Jone Sy, ‘Wadta: Walla, ‘Wash., reports that "Itihas been observed 
in both field. and: labora tory studics that the submergence of wireworms in 
saturated soil has produced’ a consistently higher mortality than in water 
alone. AS yet there is’ no’ phy siglos sical explanation - of this insect. be- 
ha vior.., 4 series ‘of. tests have bear run at constant temperatures of 869, 
61.50°, 77°, 725°, und 65° F.’ Individual wireworns were placed in vie 
of. soil and than . water was’ poured’ over the soil until it was saturated. 
An inch of weter HES képt over the surface uf the soil during. the experi- 
ment. A nunber of gr oups of 20 wiréworns each were held at..the constant 
tempera ture, toe ethos Ory cate, days. The results of: these tests on 
Boil suber gence with witcworns at arious temperatures are showing .in 
‘the ‘following table: ears eS4 iF ee pee 
“Period. of subne ergence +" <*Deres entage of-wireworns dead ‘ate 
Days 0 B8OF: 81.50 Fil 3770 FL. 42,5 Fy 680 F, 
Ae 3 95 SOS Ee, 35: + AG 
4 Tepes i2)s “O55 Seen 500 G55. ae 
se "iid oe, Cele eet oo a 
6 STOO. eee TOO OS Us 75: wih 
| 7 ibe eapen ‘ a0! : "100. ORE Vi ae aS an 75: 
a1 abies] with Ne ES vou: 100, 
bent. ose a ee eeeoniey ne ae A ae ee eee 
safer: Eis. eas 
AS shown above, a 95 perdcht 111 of wireworhs was obtained at soil 
temperatures at 81.59 F. or above in soil flooded 3 days. A temperature 
Bray (> F.. was required to obtain 100 percent kill of wireworms submerged 
for a pericd of 7 aciet ae temperatures ‘GF 68° to 72.5° F. not over 85 
percent. mortality was Latned with wireworns ea at 1 petal 
Mexican Mealybuz Controlled by Treatment wi th Spray or 
with Fumigation’ j 
H. H. Richardson, Washin igton, D. C., in his work on the Mexican 
nealybug (Phénscoccus gossypii T. and Ckli.), which is becoming a serious 
pest of er reenhouse chrysanthemums and many other ornamentals, reports that 
this pest can be controlled by spraying or fumization with hydrocyanic 
acid gas. A 1.0 percent kerosene emulsion has resulted in a 100 percent 
kill of all stages except the egg. No injury has been observed where as 
many as four applications have been made-at intervals of 4° to 9 days. 
Apparently this species differs from the other common mealybugs in being 
quite susceptible to hydrocyanic acid gas. A dosage as Low as 1/8 ounce 
per 1,000 cubic feet of space with an ‘overnizht treatment in a tight fumi- 
gation chanver resulted in a very high kill of all stages except the egg. 
_A shorter exposure, for 2 hours to’ a higher dosage (1/4 ounce) ‘was also 
effective. The several species “of” chry santhemwma: used in tests thus: ‘far have 
shown. good; tolerance > to these: ‘dosages of! cyanide. EM A oe 
“Hernist ton. Laboratory Closed 
ahs 
Note 
Os: As Hills iy being transfer od to Grand ebay Cole and the 
laboratory at Hermiston, Oreg., is being closed. 
a 
