Lidia Sukovata

Effect of Attract and Kill Formulations and Application Rates on Trap Catches of European Pine Shoot Moth (Lepidoptera: Tortricidae) and Shoot Damage in Scots Pine Saplings

Abstract Attract and kill technology was tested for management of European pine shoot moth, Rhyacionia buoliana (Denis & Schiffermüller), in 4–6-yr-old Scots pine, Pinus sylvestris L., plantations managed by Jablonna and Pultusk Forest Districts, Poland. In 2001, two formulations based on ricinoleic acid and hydrocarbon fraction (petroleum jelly) in combination with (E)-9-dodecenyl acetate, the sex pheromone of the pine shoot moth; permethrin as a contact insecticide; and Tinuvin UV absorber were used. In 2002, different formulations and application rates of the attracticide based on petroleum jelly were tested. Significantly reduced trap catches occurred in plots treated with three attracticide formulations [Rhykil-1 (with Tinuvin UV absorber), Rhykil-2 (with a new UV absorber, 3,3′-dihydroxy-2,2′-bipyridyl), and Rhykil-3 (without the insecticide)] at 3,000 droplets per hectare in comparison with those in control plots, suggesting that all formulations were highly effective. Significantly lower catches than in control plots also were observed when Rhykil-1 was applied at 1000, 2,000, and 3,000 droplets per hectare. However, only slight reduction of shoot damage in treated plots was observed in both experiments. The formulation without the insecticide had similar efficacy to that of the formulation combined with the insecticide. In 2003, the Rhykil-2 attracticide was tested at 250, 500, and 1000 droplets per hectare. Although there were no significant differences in trap catches between treated and control plots, shoot damage level was reduced substantially in all treated plots. These results suggest that attract and kill technology may be used at rates lower than 1000 droplets per hectare for management of R. buoliana; however, its “kill” effect should be confirmed in further studies.

The abundance of the nun moth and lappet moth larvae on trees of different trunk thickness in Scots pine stands in the Noteć forest complex

Liczebność gąsienic brudnicy mniszki i barczatki sosnówki na drzewach o różnej grubości w drzewostanach sosnowych Puszczy Noteckiej The abundance of the nun moth and lappet moth larvae on trees of different trunk thickness in Scots pine stands in the Noteć forest complex The size of trees varies in forests, even even-aged monocultures, and this heterogeneity may affect insect pest preferences. This paper presents the results of a study on the abundance of nun moth (Lymantria monacha) and lappet moth (Dendrolimus pini) larvae which is dependent on the thickness of Scots pine tree trunks in five forest districts in the Noteć forest complex located in western Poland. Sticky bands were installed on groups of three nearby trees of different trunk thickness categories (tree groups ABC:A - trunk thicker-, B - equal to-, and C - thinner- than the average, in a stand) in stands of different age classes, and the number of larvae trapped between 2003 and 2007 was counted. There was a significant difference in the number of larvae on trees of different thickness categories within each stand age class, when these were compared using the non-parametric Kruskal-Wallis test. These differences persisted across almost all forest districts, but mainly occurred in pine stands of age class IV (61-80 years old), which was the best represented in the samples of ABC tree groups. In these stands, there were 12.1-37.8 and 21.2-105.3 nun moth larvae/tree, and 1.9-44.3 and 3.7-78.0 lappet moth larvae/tree, on trees from categories C and A, respectively. Thus, the thicker the tree trunk, the higher the number of larvae of either species present below the sticky bands. Significant differences between stands of different age classes in the numbers of larvae below the sticky bands within each of three thickness categories were only present for D. pini in one forest district. The highest mean number of larvae (78, 58 and 44.3 larvae/tree on A, B and C trees, respectively) occurred on trees of age class IV in each tree thickness category, whilst the lowest abundance of larvae (40.7, 22.9 and 15.2 larvae/tree, respectively) was in stands of age class III (41-60 years old). Larval abundance for both insect species directly depended on tree thickness, indicating some preference for large trees by L. monacha and possibly D. pini females for oviposition, and by D. pini larvae migrating in spring from forest litter into tree crowns for feeding. This dependence was apparent only when the number of larvae on trees of the same age class were compared, thus it was not related to differences in tree thickness due to tree age. Given the possible reasons behind insect preferences, we suggest that: a) thinning of Scots pine stands is conducted to leave the most homogeneous stand structure of trees possible, with respect to their thickness (trunk size) to minimise a potential increase of L. monacha and D. pini population density, b) more than three trees per stand are monitored using sticky bands during the early spring to estimate abundances of both insect species, and c) an equal proportion of trees from each thickness category is examined during the spring; this will allow foresters to avoid over- or underestimation of population densities and, in consequence, the threat posed by these insect pests.