Pine Bark Beetles in Florida

More than 30 species of bark beetles are associated with pine trees in Florida, but only five species are likely to be serious pests. These species, pictured above, are easily distinguished based on a few morphological and behavioral characters. Adults are separated into the two genera based on the posterior declivity being either rounded and smooth or depressed and surrounded by spines. Size alone is enough to distinguish between the two species of Dendroctonus, while size and the number of spines will separate the three Ips species. The size, shape, and location of the galleries made by adults and larvae as they move through the inner bark can also be used to identify these bark beetles.

More information about each species is presented below.

 

Characters for distinguishing the southern pine beetle include:

• Adults 2-3 mm (1/8 inch) long; declivity (hind end) rounded, without spines.
• Parental galleries winding, frequently overlapping, and packed with frass except for the portion where the male and female are working; eggs laid in individual niches at intervals of about 6 mm (1/4 inch).
• Larval galleries short (5 to 10 mm), and then curving into the outer bark where pupal cells are formed.
• Pitch tubes, if present, 6-13 mm (dime size) in diameter; yellowish-white on loblolly pine, runny brown on slash and longleaf pines; more likely to be in bark crevices rather than on bark plates.
• Attacks generally begin below the lowest branches and may eventually extend from the lower bole up into the lower crown.

 

Characters for identifying the black turpentine beetle include:

• Adults 5-8 mm (1/4 to 1/3 inch) long, the largest bark beetle in the South; declivity (hind end) rounded, without spines.
• Parental galleries start with a short horizontal segment, then turn downward. Eggs deposited in groups along the side of the gallery.
• Larvae feed side-by-side, excavating a cavity in the phloem.
• Pitch tubes large, often 25 mm (1 inch) in size.
• Attacks generally limited to the lower 2 meters of the tree.

 

Characters for distinguishing the fourspined Ips include:

• Adults 2-3 mm (1/8 inch) long, the smallest of the three Ips; declivity concave with 4 spines on each elytron.
• Parental galleries mostly straight and with the grain. Galleries clean, without the boring dust typical of SPB galleries. Eggs laid singly and often on just one side of the gallery.
• Larval galleries expand gradually for a short distance, then terminate in a large feeding and pupation cell.
• Pitch tubes, if present, reddish-brown owing to the boring dust ejected by the parent beetles.
• Attacks generally restricted to the branches and upper bole of large trees; often the only bark beetle found infesting small pines.

 

Characters for distinguishing the eastern fivespined Ips include:

• Adults 3-4 mm (1/6 inch) long, intermediate in size between the other species; declivity concave with 5 spines on each elytron.
• Parental galleries often Y- or H-shaped as females tunnel away from the entrance cavity created by the male. Eggs laid singly and often on just one side of the gallery.
• Larval galleries gradually enlarging as the larvae feed and grow; no terminal cells as in Ips avulsus.
• Pitch tubes reddish-brown and most likely located on bark plates rather than in crevices.
• Attacks on standing trees most likely to be on the upper trunk and the bases of the larger branches.

 

Characters for distinguishing the sixspined Ips include:

• Adults 4-6 mm (1/4 inch) long; declivity concave with 6 spines on each elytron.
• Parental galleries larger than, but otherwise similar to those of Ips grandicollis. Eggs laid singly and often on just one side of the gallery.
• Larval galleries similar to those of Ips grandicollis.
• Pitch tubes reddish-brown and most likely located on bark plates rather than in crevices.
• Attacks commonly found on the trunks of large trees; rarely infests material less than 10 cm (4 inches) in diameter.

Additional online information available at:

• The Southern Pine Beetle in Florida
• Quick facts about SPB biology and control.
• Frequently asked questions about southern pine beetle control.
• The Southern Pine Beetle Information Directory -- Link to Southwide information about the SPB

Prepared by John L. Foltz, 17 Nov 1997. Last modified 4 June 2001.