Termites attack

Copper-treated stakes prevented termite attack 15... 

Rowell etal. (1987b) produced PF-bonded flakeboard from acetylated southern pine (21.6 % WPG) or aspen (17.6 % WPG) flakes. This was not completely resistant to attack by termites Reticulitermes flavipes) in a 4-week test. It was thought that acetylation was less effective in preventing termite attack than other chemical modifications because cellulose decomposition in the intestines of termites leads to acetic acid formation in any case. 

Pine sapwood acetylated to 22 % WPG exposed for 1 year at an outdoor test site in Indonesia showed a weight loss of only 2 % due to termite attack, whereas unmodified controls lost 93 % in weight in the same period (Westin etal, 2004b). 

Particleboards and flakeboards made from acetylated flakes have been tested for resistance to several different t5 pes of organisms. In a 4-week termite test using Reticulitermes flavipes (subterranean termites), boards acetylated at 16 to 17 WPG were very resistant to attack, but not completely so (, 36,37) This may be attributed to the severity of the test. However, since termites can live on acetic acid and decompose cellulose to mainly acetic acid, perhaps it is not surprising that acetylated wood is not completely resistant to termite attack. 

Wih respect to the insecticide activity, Podocarpus macrophyllus is widely known in Japan for its resistance to termite attack. Saeki disclosed in 1970 that the termiticidal activity is entirely due to inumakilactone A (28) and another unidentified compound of similar structure, the former being more active [70]. This second compound was later reported to be nagilactone D (4). 

In preliminary tests, alkylene oxide-treated southern pine (28) was found to be resistant to termite attack and attack from the marine borers, Teredo (shipworm) and Limnoria. 

Mahogany is any of the hardwoods in the family Meliaceae. These trees are found in the Caribbean, Central and South America, Asia, and Africa. The wood resists termite attack, is easy to work, and has a beautiful reddish hue when polished. Its water resistance made it attractive to ship builders, who used it whenever it was available in sufficient amounts. 

Table 6 Weight Lx)ss (WL) of Formalized Cedar and Beech Blocks Due to Termite Attack After Forced-Feeding Tests with Coptotermes formosams for 9 Weeks and with Reticulitermes speratus for 2 or 4 Weeks...

The molecular weight of PF resin affected termite resistance less clearly than decay resistance, but resins with up to 621 Mn gave better termite resistance than larger molecular weight resins. Although total elimination of termite attack was not achieved by any PF resin treatment, activities of termites fed on the treated wood declined at a greater rate than that of starved termites. At 10% of WPG, all treated blocks caused a 100% mortality of termites after 6 or 7 weeks feeding. 

Treatments 1-4, 9, 11, and 13 were highly effective against termite C. formosanus (Table 15). When a small amount of boric acid was added to anion solution, 100% mortality was achieved in all cases regardless of WPG values. Barium hydrogen phosphate appeared to perform better than any of the other deposits. Barium sulfate also succeeded in controlling termite attack with the aid of boric acid in both treatment solutions or in the second solution. 

Property enhancement by acetylation has been frequently reported over the years in other reconstituted wood products such as flakeboards, particleboards, and fiberboards [8,9,11,12,59-64]. Table 16 shows the laboratory decay test of low-density acetylated particleboards made from perishable albizzia wood. They were resistant to attack by Tyromyces palustris (brown rot), Coriolus versicolor (white rot), and Chaetomium globosum (soft rot) above 12% WPG. These acetylated boards with 20% WPG also exhibited an improved resistance to attack by the destructive Formosan termite, Coptotermes formosanus, in the laboratory. However, their performance was unsatisfactory in the wet tropics with a higher hazard of termite attack. High resistance to fungal and bacterial attack in acetylated southern pine and aspen flakeboards was evidenced in laboratory and fungus cellar tests [12]. 

Figure 3 shows that after only 2 weeks of termite attack the control specimen is almost completely destroyed. The epoxide-modified block suffered only minor damage, because the termites did some surface grazing but did not attack. 

Figure 3. Butylene oxide-modified block (left) and control (right) after 2 weeks of termite attack.

The abundance of the resource and the highly desirable strength properties have led to widespread use of treated Douglas-fir with subsequent biodegradation problems occurring in poorly treated products (18). Extensive research has been carried out to develop fumigant treatments for internal decay in poles (J9). In Hawaii the problems of termite attack are being considered now (20, 21). 

Use To stop wood rot, termite attack, mildew, and decay. 

Camphor and <7-limonene are allomones in that the trees which produce them are protected from insect attack by their presence. For instance, Arthur Birch, one of the great terpene chemists of the twentieth century, reported finding d-limonene in the latex exuded by trees of the species Araucaria bidwilli.1 2 These trees are protected from termite attack because the d-limonene they produce is an alarm pheromone for termites that live in the same area. Similarly, antifeedants could be considered to be allomones since the signal generator, the plant, receives the benefit of not being eaten. Myrcene is a kairomone, in that it is produced by the ponderosa pine and its presence attracts the females of the bark beetle, Dendroctonous brevicomis. Geraniol is found in the scent of many flowers such as the rose. Its presence attracts insects to the flower and it can be classified as a synomone since the attracted insect finds nectar and the plant obtains a pollinator. 

Uses Biocide for water treatment, cooling water systems, evaporate condensers, pulp/paper, antifoulant paints, leather, timber preservation, oil well brines and drilling muds wood preservative (stops wood rot, termite attack, mildew, and decay) algicide fungicide bactericide slimicide in paper mills, food-contact paper/paperboard preservative for paints, adhesives, syn. polymer latexes, latex emulsions antimicrobial for aq. prods., thickeners, slurries Regulatory FDA 21 CFR 176.300... 

Uses Microbicide, antimicrobial, bactericide, fungicide, preservative in textiles, paints/coatings, adhesives, caulks, sealants, cutting fluids, and metalworking fungicide for wood slimicide in food-contact paper/pa-perboard seed treatment for barley, cotton, wheat, etc. wood preservative to stop wood rot, termite attack, mildew, and decay Regulatory FDA 21CFR 176.300... 

Two scales are used for the evaluation of wood damage by termites. The older of the two scales, and the one most commonly used by the Forest Service, is the GulQ)ort Scale, which was developed over 40 years ago. It has values of 0 (no evidence of termite attack), 1 (nibbles to surfttce etching, no penetration), 2 (penetration, limited damage), 3 (general damage), 4 (heavy damage) and 5 (destroyed) (6). 

In 1994, Termidor 80 WG (Rhdne-Poulenc), the active ingredient of which is fipronil, was installed in Forest Service field tests in a conventional layout. Figure 5 shows the number of years without termite attack for Termidor 80 WG in the concrete slab tests. As of 2003, there were no termite attacks at any of the plots at the four sites, down to the lowest labeled rate of 0.0625% a.i. However, it was noticed that termite pressure in the fipronil control groups at all four sites was less than expected (Figure 6, shaded bars). Termite attack in the control plots rarely surpassed about 30%. The simplest explanation for this was that it was simply a bad time for termites and termite pressures were low, leading to low attack rates at the control plots. If this were the case, it could not be said that the results in the test plots were due to the presence of fipronil it may simply be that there were few termites present. This presented a significant problem for regulatory officials. 

Examination of other tests at the same locations in the same years, however, revealed that termite attack on the control plots of other tests at the same site were, in all cases, notably higher than those in the fipronil test (Figure 6, open bars). So it seemed that the lower termite pressure was confined to the study containing fipronil, a phenomenon dubbed the area effect. ... 

Figure 5. Years without termite attack as of2003 for Termidor 80 WG for the concrete slab test in the conventional layout. The dashed line represents the EPA s five-year testing requirement This product is labeled for use at the 0.0625 and 0.125% rates.

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