NORTHEASTERN FOREST EXPERIMENT STATION 

Upper Darby, Pennsylvania 

No. 67 

19 57 

WEEVIL ATTACKS APPARENTLY UNRELATED 

TO HEIGHT OF EASTERN WHITE PINE 

As individual eastern white pine trees grow taller, 

are they less susceptible to attack by the white pineweevil? 

At what height are they most likely to be attacked? 

If weevil injuries on 97 eastern white pine trees 

(387 logs) from the Pack Demonstration Forest, Warrensburg, 

N. Y., are indicative of weevil behavior elsewhere, the 

white pine weevil (~issodes strobi) is neither hindered nor 

abetted by the relative height of its host. Apparently the 

chances of an individual tree 's being attacked are not influenced by the tree 's height (table 1). 

These data on the relationship of tree height to 

weevil injury were collected during a recent study of white 

pine log defects. The study was conducted on the Pack Forest by research personnel of the State University of New 

York, College of Forestry, and the U. S. Forest Service, 

Northeastern Forest Experiment Station. The trees were 

felled and the location and nature of various log defects, 

including apparent weevil in juries, * were noted. Threehundred-sixty-two apparent weevil in juries were diagrammed. , 

When the logs were sawed into lumber, a total of 456 

actual weevil injuries were discovered. This indicates a 

ratio of 5 actual weevil attacks for every 4 that could be 

detected from external indications. 

Because the trees were selected to provide a range of 

butt-log grades, the total incidence of v~eeviling is not 

necessarily typical. But this method of sampling resulted 

in a wide range of tree ages (45 to 120 years), tree sizes, 

sites, species, and age-class mixtures, and trees frequently 

and infrequently attacked (0 to 11 injuries per tree). 

Periodic fluctuations in weevil attack were not libely to 

have had any influence on this tree height-susceptibility 

relationship because the trees differed in height in any 

year. Because some trees were taller than others when cut, 

the number of sample sections decreased as tree height increased**; yet it is apparent thet the degree of weeviling 

*IN THIS REPORT. 'WEEVIL* INJURY OR ATTACK REFERS TO ALL WEEVIL AND WEEVILLIKE INJURIES OBSERVED. ALTHOUGH SOME OF THESE MAY HAVE BEEN CAUSED BY BIRDS. 

SQUIRRELS . OR OTHER INSECTS . 
Table 1.-Height of weevil attacks on 97 white pine trees at Pack Forest, 1955" 

-% 

Based on actual weevil injuries observed on lumber sawed from logs studied. 

at heights over 60 feet was as great as that for trees 10 to 

20 feet tall.*** 

These observations raise serious doubt about the 

commonly held belief that weevil attacks will be less frequent as individual host trees grow taller. If taller, older 

trees are attacked as frequently as others, weevil-control 

measures that can be applied only to the first log may be 

inadequate where long rotations are planned and quality of 

the upper logs is crucial. And when plsntations are sprayed 

to c~ntrol weevil damage, nearby older stands may also have 

to be treated if immediate re-infection is to be avoided. 

Because the sample trees were taken from one localized area, the Pack Forest, final conclusions must await the 

results of additional studies. More information on this 

question may be expected as additional data is collected in 

New Hampshire and Maine in connection with later phases of 

the StationJs study of log grsdes for eastern white pine. 

--MYRON D. OSTMNDER 

Forest Econorist 

Northeastern Forest Experiment Station 

Forest Service, U .S. Dept . Agriculture 

**rlr IN 21 TREES. ADVANCED DECAY MADE WEEVIL IDENTIFICATION IN THE LOWER PART 

OF THE BUTT LOG DIFFICULT. THIS MAY ACCOUNT IN PART FOR THE SOMEWHAT LOWER INCIDENCE RATE IN THE LOWEST TWO OR THREE 5-FOOT SECTIONS.