Maarit Kytö. (1992). Lygus bugs as agents of growth disorders in permethrin-treated pine seedlings in regeneration areas. Silva Fennica vol. 26 no. 4 article id 5487. https://doi.org/10.14214/sf.a15648

Keywords: Pinus sylvestris; growth disorders; seedlings; Lygus; permethrin; bud disorders

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The ability of Lygus bugs to cause growth disorders in permethrin-treated Scots pine (Pinus sylvestris L.) seedlings after planting was studied in two regeneration areas. There were three treatments: exposure of the seedlings to Lygus, mechanical protection of the seedlings from insects, and control seedlings. There were no significant differences in the rate of growth disorders between the treatments. The permethrin application protected the seedlings against Lygus bugs in the early summer, as well as when the bug abundance was low. The development of these seedlings, as well as the multiple-leadered and bushy seedlings on a third regeneration area, was followed for two years. Multiple leaders reduced height growth and bud number of a seedling, but caused marked losses in growth only when the seedlings still had multiple leaders the following year, or when they formed several, equally developed stems.
The PDF includes an abstract in Finnish.

Kytö, E-mail: mk@mm.unknown

Category : Research article

article id 373, category Research article

Anna Saarsalmi, Pekka Tamminen. (2005). Boron, phosphorus and nitrogen fertilization in Norway spruce stands suffering from growth disturbances. Silva Fennica vol. 39 no. 3 article id 373. https://doi.org/10.14214/sf.373

Keywords: Norway spruce; fertilization; needles; height growth; recovery; boron; growth disorders; soil

Abstract | View details | Full text in PDF | Author Info

Growth disturbance symptoms typical of B deficiency have been reported on Norway spruce (Picea abies (L.) Karst.) trees in many parts of eastern Finland. In order to test the B deficiency hypothesis and explore the possibilities of curing the disturbed trees with B fertilization, three experiments were established in October 1999 in young Norway spruce stands growing on fertile sites in eastern Finland. All the stands contained healthy, slightly and severely damaged trees with growth disturbances typical of B deficiency (B < 5 mg kg–1). 40 healthy, 40 slightly damaged, and 40 severely damaged trees were selected as sample trees in each stand. In May 2000, the trees were fertilized with 2.0 kg B ha–1 as borax (B), 2.0 kg B ha–1 and 40 kg P ha–1 as superphosphate (B+P) or 200 kg N ha–1 as urea (N). The control trees were not fertilized (0). The needle response to B fertilization was rapid, relatively high B concentrations being achieved already after one growing season. Boron fertilization cured the growth disorders and increased height growth within four years, but had no effect on diameter growth. The trees also recovered without B fertilization, but to a lesser extent compared to the B fertilized trees. Compared to the control, boron fertilization increased the height growth in all the disorder classes, i.e. 5, 17 and 19 cm yr–1 for healthy, slightly and severely damaged trees, respectively. As the healthy trees also seemed to benefit from B fertilization, this indicates that B deficiency in fact retards height growth before any disorder symptoms become apparent in individual trees. Compared with B alone, the application of P together with B gave no additional benefit. Nitrogen fertilization alone appeared to have a detrimental effect on height growth in the severely disturbed trees.

Saarsalmi, The Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: anna.saarsalmi@metla.fi
Tamminen, The Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: pt@nn.fi

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