NORTHEASTERN FOREST EXPERIMENT STATION 

Upper Darby, Pennsylvania 

No. 78 

1958 

CONTROL OF THE WHITE-PINE WEEVIL 

WITH INSECTICIDAL EMULSIONS 

Excellent control of the white-pine weevil in young 

white pine plantations, by applying concentrated lead arsenate spray with knapsack sprayers, was demonstrated and reported several years agoml Since then, research has shown 

that a number of newer insecticides, used as emulsions, are 

also very effective. 

Emulsions have the following advantages: (1) they are 

easy to prepare and apply, (2) they offer a wide range of 

materials that are not injurious to the trees, (3) they can 

be effective against other insects such as the pine bark 

aphid, (4) their costs are relatively low, and (5) it is 

possible to lengthen their period of effectiveness considerably by the use of an extender. 

Replicated tests under conditions of heavy weevil 

populations have proved the following emulsions completely 

satisfactory for use in March and April: (1) DDT at 1 percent; (2) heptachlor, 1 percent; (3) heptachlor plus extender, % percent; (4) lindane plus extender, 114 percent; and (5) 

malathion plus extender, 1% percent. (Endrin was alsotested, 

and it proved effective for killing white-pine weevils. However, it cannot be recommended for general use because it is 

extremely toxic to wildlife.) 

lcrosby, David. How to control the white-pine weevil 

with a hand sprayer. Northeast. Forest Expt. Sta. Forest 

Res. Note 30. 3 pp. 1954, 
Fall applications in late October, using lindane plus 

the extender at 2, 1, and % percent, resulted in only 1 weeviled leader out of 10,000 trees sprayed. Fall treatments 

with 3- to 5-percent emulsions of heptachlor, plus the evtender, also appeared very promising. 

Spray Materials 

Insecticides.--The formulations recommended are prepared from the following emulsifiable concentrates: (1) DDT, 

25 percent; (2) lindane, 20 percent; (3) heptachlor, 25 percent; and (4) malathion, 57 percent. Simply add water t~ the 

concentrate or to the concentrate plus the extender. (See 

Table 1 for proportions.) 

Extender. --Aroclor 54602 is available in rosin-like 

form from Monsanto Chemical Co. A 75-percent stock solution 

is prepared by dissolving 1 pound of Aroclor 5460 in 1 pint 

of technical grade xylene. Thus far, this solution has been 

used in equal part by weight with each insecticide. 

Equipment 

Sprayer.--A wide range of equipment, from simple hand 

sprayers to 5-gallon knapsack sprayers, is available for applying these emulsions, The cylindrical 2- or 3-gallon 

compressed-air garden sprayer is satisfactory for small tree 

applications, easy to use, and relatively low in cost. 

Nozzle.--For proper economy of materials, only very 

fine nozzle openings should be used. The wl-S" nozzle recommended for lead arsenate is quite satisfactory, but many 

other nozzles will suffice. Under general field conditions, 

the nozzle delivery rate should be 1 to 2 gallons per hour. 

Spray Rod.--A light tubular rod about 4-feet long 

will handle conveniently all trees up to 10 feet in height. 

A 90° elbow on the nozzle end is highly desirable. 

Strainer.--To avoid clogging, all materials put into 

the sprayer should be strained through either fine metal 

2~ention of commercial products is not to be construed as endorsement of them by the Forest Service or Department of Agriculture. 
cloth (about40 mesh), or several thicknesses of cheesecloth. 

Measures.--For preparing the emulsions, you will 

probably need the following liquid measures: 1-gallon, 1- 

quart, and 1-pint graduated in ounces, 

How To Spray 

The upper half of each leader should be sprayed to 

the run-off point by holding the nozzle 1 to 4 inches from 

the leader. Spray the leader from opposite sides to insure 

proper coverage. 

When To Spray 

Spraying may be done in March and April or in the 

fall, depending on the material used. Spring spraying should 

be completed by late April or early May before the adult 

weevils commence feeding. 

Recommended Sprays 

Emulsions now recommended are given in Table 1. Formulations numbered 1 to 5 are for spring treatments; and 6 to 

7 for fall treatments. These recommendations are tentative 

and may ultimately be changed. 

Of the formulations in Table 1, some preference may 

be given lindane because of its low cost and malathion for 

its low toxicity to mammals. 

Selective Spraying Or Partial Treatment Of Stand 

Protecting a stand of young white pines with hand 

equipment can be accomplished with less expenditure of time 

and money if only the well-formed vigorous trees are sprayed. 

However, when only part of the stand is sprayed, it is essential that the stand be examined by mid-July and any 

weeviled leaders removed and destroyed. This partial treatment will reduce the chances of weeviling even on the untreated trees. Tests conducted over the past 3 years indicate that the degree of weeviling of the untreated trees 

will be less than one-fourth that in comparable check areas. 

Weeviling on the sprayed trees has in all cases been less 

than '/I? percent. 
Table 1.--Recommended emulsion sprays for control of white-pine weevil 

I I 1 I I I 

Per- Fluid Fluid 

- cent - 02. - 02. a 6 0) a 0 -4 

1 DDT, 2% 25.0 10.2 -- 0) rl $0.34 0) (Il 

2 

I ":::' / Formulation 

Heptachlor, 2% 25.0 

Heptachlor, 1% - A** 25.0 

Lindane, %? % - A* * 20.0 3.2 .9 5 2 

9 G *23 I 

Commercial 

concentrate 

1 Malathion, 2% - A** 57.0 4.5 3.4 E s4 '41 1 

Heptachlor, 4% - A** 25.0 a 0) 

20.5 6.8 I Lindane, 1% - A** 20.0 6.4 1.7 a o " d 4 0 046 1 

To make 1 gallon, use-- 

Concentrate I Extender I Water 

*Based on 1957 retail costs. 

**Equal parts by weight of Aroclor 5460 and insecticide. 

Cost per 

Many more trees can be sprayed per gallon and per 

hour by selecting only the good trees for treatment. In 

plantations 3 to 8 feet in height the following may be expected: (a) spraying all trees--320 per gallon and 450 per 

hour; (b) spraying only good trees--450 per gallon and 650 

per hour. The combined costs of spraying only the good trees 

plus the removal of weeviled leaders in mid-July should be 

75 percent or less of the cost of initially spraying all the 

trees in the plantation. 

--DAVID CROSBY 

Entomologist 

Division of Forest Insect Research 

Northeastern Forest Experiment Station 

Forest Service, U.S. Dept. Agriculture 

AGRICULTURE- FOREST SERVICE- UPPER DARBY