Adding knowledge to the impact and ecology of the seed bug, Leptoglossus occidentalis, on stone pine
There is still a substantial lack of knowledge about the effective impact and the ecology of the seed bug, Leptoglosus occidentalis, on the Mediterranean stone pine. Thus, the overall objective was to characterize the impact and study the ecology of this invasive insect in stone pine by (1) characterizing its damage on seeds with shell; (2) testing its preference between stone pine and other Mediterranean pines; (3) evaluating damage in Stone pine seed orchards under different management strategies and (4) inferring invasion routes of this insect in the Iberian Peninsula using genetic and field data.
In order to contribute to greater market transparency, APFC - Associação de Produtores Florestais, conducts an impartial sampling and issues since 2015 a press release on pine cone average yields in the Coruche region (Portugal).
For the fifth consecutive year, APFC has used a methodology for sampling the cone quality at 8 sites throughout the municipality of Coruche in order to represent the entire area of pine production.
Each sample has 10 cones harvested randomly from each of 30 trees per site. The cones are weighted before opening, the inshell pine nuts are removed mechanically and shelled manually (sample of 2 kg). The kernels are weighed at a reference humidity (9%) and referred to the cone weight.
The aim of this work was to quantify the extent of the recent decline observed in pine nut and kernel production. For this purpose, we analysed data from the INIA long-term sample plot network for cone and pine nut production in the four main Spanish stone pine regions. Data series for more than a hundred plots since the last century, previous to the arrival of the bug, were compared with the same series after its arrival. Hence, the collapse in kernel per cone yield since can be quantified, the implied main factors identified, and the evidence of L. occidentalis causality implied analysed.