Fine root biomass and production in Scots pine stands in relation to stand age

We determined fine root biomass and production of 15-, 35- and 100-year-old Scots pine (Pinus sylvestris L.) stands during three growing seasons. Fine roots were sampled by the soil core method. Mean (+/- SE) annual fine root biomass of Scots pine in the 15-, 35- and 100-year-old stands was 220 +/- 25, 357 +/- 21 and 259 +/- 26 g m(-2), respectively. Fine root biomass of the understory vegetation was 159 +/- 54 g m(-2), 244 +/- 30 and 408 +/- 81 g m(-2), and fine root necromass was 500 +/- 112, 1,047 +/- 452 and 1,895 +/- 607 g m(-2) in the sapling, pole stage and mature stands, respectively. Both understory and Scots pine fine root production increased with stand age. Mean annual Scots pine fine root production was 165 +/- 131, 775 +/- 339 and 860 +/- 348 g m(-2) year(-1) in the sapling, pole stage and mature stand, respectively. The respective mean annual production of all fine roots (Scots pine and understory) was 181 +/- 129, 1,039 +/- 497 and 1,360 +/- 869 g m(-2) year(-1). The Scots pine and understory fine root biomass, necromass and production varied in relation to stand age, although the variation was not statistically significant.     

Impact of alpha-cypermethrin on honey bees foraging on spring oilseed rape (Brassica napus) flowers in field conditions

BACKGROUND: Cruciferous oil-bearing crops have gained in importance worldwide. The expansion of the growing area of these crops has caused a proliferation of pests. Exposure to organophosphate, carbamate and pyrethroid insecticides has been associated with bee poisoning in food crops. This study examines the repellent effect of alpha-cypermethrin on the number of foraging honey bees, Apis mellifera L., on fields of spring oilseed rape, Brassica napus L. var. oleifera. RESULTS: The first experiment was conducted on differently sprayed 10 m(2) experimental plots where alpha-cypermethrin was applied at different times. Another experiment was conducted on a 4 ha seed production field divided into two parts: one part was treated with alpha-cypermethrin and the other was not treated with this insecticide. The results show that there was no difference in the number of honey bees between alpha-cypermethrin-treated and untreated patches. The result persisted through three observation years, regardless of varying flower and honey bee densities. CONCLUSION: No repellent effect of the insecticide on honey bees was found even 24 h after spraying. The density of oilseed rape flowers most likely played a major role in choosing the foraging area.     

Circumferential variation of heartwood and stem quality in maritime pine stems

Maritime pine (Pinus pinaster Ait.) is an important timber and pulpwood species covering about 4 million ha in Portugal, Spain and France. This work studied the cross-sectional distribution of heartwood and sapwood along the stem using 3D modelling on 20 trees. The target was to assess the potential of this species for the industrial production of heartwood sawn products. The maritime pine stems were characterized by wide sapwood of 10 cm, in average, and the presence of heartwood at all height levels with constant diameter up to 35 % tree height, decreasing afterwards. In the radial section, the heartwood follows a circumferential-like shape which changes along the stem. Pith eccentricity index values were low and homogeneous regarding to stem and higher for heartwood. Heartwood cross-sectional shape was constant up to 45 % of total height of the tree and more elongated upwards. The constant heartwood diameter, low taper and pith eccentricity index, and an approximate circular shape up to 10 m height indicated these species’ potential to produce solid wood products made out of heartwood.     

The structure of mating type,virulence, metalaxyl resistance of Phytophthora infestans in a long-term phenotypic study in distinct location in Eastern Estonia

Journal of Plant Diseases and Protection - The potato late blight pathogen Phytophthora infestans was collected from a region of Eastern Estonia during a period of seven years (2001–07). In...     

The structure of <Emphasis Type="Italic">Phytophthora infestans</Emphasis> populations from organic and conventional crops

The characteristics of populations of Phytophthora infestans from organic farms, small conventional farms and large conventional farms were determined from isolates collected in northern Estonia in 2004 and 2005. For the population as a whole 41% were A2; all virulence factors to the 11 R genes from Solanum demissum were found; and more than 70% had high or intermediate resistance to metalaxyl. Isolates from organic farms tended to have more complex pathotypes than isolates from either large or small conventional farms, but there was a higher proportion of metalaxyl resistant isolates from large conventional farms than from small conventional farms or from organic farms.     

Nasopharyngeal trichobezoar foreign body in a cat

CASE SUMMARY: A 5-year-old male neutered indoor cat presented for evaluation and treatment of an acute onset of nasal discharge and open-mouth breathing of 3 days' duration. He had been treated for asthma prior to presentation, but his clinical signs were more consistent with upper airway disease. Thoracic radiographs were suggestive of asthma. However, a soft tissue mass was noted in the nasopharynx on a lateral cervical radiograph. Nasopharyngeal examination revealed the mass to be a trichobezoar (hair ball) lodged in the nasopharynx, removal of which led to resolution of clinical signs. The cat re-presented with a second nasopharyngeal trichobezoar approximately 1 year later, which was also successfully removed. CLINICAL SIGNIFICANCE: Nasopharyngeal disease has myriad potential infectious, inflammatory and neoplastic etiologies. However, simpler causes such as foreign bodies can be considered in cases of acute-onset nasopharyngeal disease. To the authors' knowledge, this is the first reported case of a nasopharyngeal trichobezoar foreign body in a cat.     

Zinc phosphate protects tomato plants against Pseudomonas syringae pv. tomato

Journal of Plant Diseases and Protection - The purpose of this study was to determine whether zinc phosphate treatments of tomato plants (Solanum lycopersicum L.) can attenuate bacterial speck...