Effect of weed elimination treatments on survival, growth and important pest population of poplars in the nurseries of Safrabasteh research station, Guilan province

Poplar is a one of the fast growing and prolific species that is used for afforestation programs. Advising agro-technical methods with attention to ecological aspects is one of the effective and important factors in integrated management of pests. The object of this investigation is studying the effects of different weeding treatments (complete weeding, monthly weeding and no weeding) on diameter and height growth of poplar seedlings, evaluating variation of different weeding treatments and also identifying weeds of poplar nurseries and studying their effects on population densities of Chlorophanus votuptificus, Slatymycterus marmoratus, Stauronematus compressicornis and Paranthrene tabaniformis, which are important pests of poplars in the nurseries. Statistical analysis of the obtained data did not show any statistical differences between the treatments in survival percentages of the seedlings. Diameter and height growth of healthy and infested seedlings to poplar gall inducing moth was not affected by weeding treatments in the years 2001-2002. However, in the years 2003-2004, a significant difference was observed between different weeding treatments in diameter and height growth of seedlings (P<0.01). The three weeding treatments had no significant effect on population densities of Chlorophanus votoptificus, Stauronematus compressicornis and Paranthrene tabaniformis, but in 2004, density of this pest was different in various treatments and a significant difference was observed in P<0.01. The highest number of insects was in monthly and the least was in weakly weeding treatment.