26 ANNUAL RBFOBTSOf DEPABTMBNT OF AGHICULTUEB, 1949 
apple- in Indiana and four applications of U to 2 pound- L r avc 
complete control on peach in Georgia, A - i i . i_r 1 * - summer application 
of one-halfpound of 25 percent parathion per LOO gallons gave partial 
control of Fori* — cale on apples. During the dormant period, how- 
ever, a Bingle application of ] \ to 2 pounds per LOO gallons 
w as ineffect ive against the San Jose -cale on peaches, the control rang- 
ing from 11 percent for the higher dosage to none for the Lower one. 
Parathion showed promise for the control of scale insects on citrus. 
In Florida sprays containing one-half pound of actual parathion 
100 gallons gave good -cale control whether prepared from wettable 
powders or emulsion concentrate-. The indicated effectiveness of ■ 
parathion-wettable sulfur spray has given Impetus to the effort 
develop a safe and effective combination spray to control the Florida 
red scale, purple scale, and citrus rust mite. At present materials 
recommended for combating these pests must be applied separately 
and only with a safe interval between applications. 
In California parathion wettable powders appeal- to be at least 
as effective as conventional oil sprays against the California red 
scale, and the combination of j •_- to 1 pound of 25-percent parathion 
wettable powder per LOO gallons with an oil spray has given even 
better results. Wetting agents did not increase the efficiency of sprays 
containing parathion wettable powders when used against the Cali- 
fornia red -•■ale. and there was little advantage in increasing the con- 
centration from 1 to 2% pounds of the 25-percent wettable powder 
per LOO gallons. In California the percentage kill of scales wa- not 
affected by population density a- it i- when oils are used. Parathion 
appears to he somewhat more effective against scales on the old wood 
of citrus, whereas oil i- generally most effective against scales on the 
new green wood and on fruit. Parathion caused a little injury to 
lemon foliage. 
Parathion also gave almost complete control of the (in- scale on l]<r 
fruit in California when applied early in May. From in to 20 ounces 
of 25-percent wettable powder per LOO gallons was used with a small 
(plant ity of summer oil. 
Hall Srale Eradication 
All trees in the ChlCO and Oroville area- of California known to be 
infested with the Hall scale were fumigated i'^v the second successive 
year- during the winter of L9 I s 19. For some I rees this was the third 
or fourth annual Fumigation. Although spot inspections have shown 
that a few scales can -urvive a single film 'mat ion. no living scales have 
yet been found on trees Fumigated more than once. A- soon a- trees 
fail to yield live -cale- after each of three successive annual fumiga- 
tions, tiiey will not be subjected t<> further treatment unless there i- a 
recurrence of infestation, [nspections will be continued for at least 
:; rears after the treatment Is discontinued. 
A new infestation involving L0 properties containing! , 815 host t rees 
was found in the vicinity of Bidwell Park- at Chico in June 1949. In 
dications are that this infestation originated with the movement of 
plants from the Plant Introduction Garden at Chico. 
