Gyropsylla spegazziniana (Lizer, 1917) (Hemiptera, Psyllidae) or "ampul" is a pest of paraguay-tea (Ilex paraguariensis) that provoques the growth in the structure of new leaves for ninfal protection. Leaves with these symptoms fall after insects left causing produtivity reduction. To study the environmental factors interference in the population flutuation of this pest, two orchards were biweekly sampled from 1997 to 2000 in Chapecó, SC. The samples were evaluated in the Agricultural Research Enterprise - Epagri/CPPP, and totaled 21,044 insects with 0.42% of sexual ratio. Correlation analyses between insects captured from 1998/2000 and monthly mean minimum temperature (Tmi) accused r = 0.63 and the linear regression analyses showed the equation <img src="http:/img/fbpe/cr/v32n3/a04img01.gif" align="absbottom"> = - 1,621.47 + 156.37 Tmi, with r² = 0.40. The basic temperature (Tb) of 10.36ºC was obtained by giving value zero to this equation. The thermal constant (K) of 399.52 day-degrees (GD) was calculated using K = D (T - Tb), in which "D" was 27.29 the days of biological cicle of "ampul", with 25 ºC (T). The 3,219.30 annual GD was calculated with the mean of the total sum of monthly mean medium temperature, lessenig from Tb and multiplicating number of days, in the months in which Tmi > Tb. The annual GD divided to CT resulted in 8.05 possible annual generations of this insect.
paraguay-tea; Ilex paraguariensis; insecta; annual generations; day-degrees
