Medicinal plant bioactivity – Catuaba (Anemopaegma arvense (Vell) Stellfeld JF & de Souza) on Spodoptera frugiperda (JE Smith) Lepidoptera: Noctuidae) in the larval stage

Catuaba (Anemopaegma arvense (Vell) Stellfeld JF & de Souza (Bignoniaceae) is a medicinal plant used as aphrodisiac. Biocidal effect of A. arvensewas evaluated on the larvae of Spodoptera frugiperda. Plant leaves were collected in Cáceres (MT, Brasil) to make a Catuaba crude methanoic extract (EMeC). Five 50 mL concentrations were used to make the treatments: (T0=0, distilled water; T1=2,250; T2=4,500; T3=9,000 and T4=18,000 ppm). It was used 120 third instar larvae of the second generation, raised at 30±3°C and relative humidity of 60±10%. Under the effect of the treatments, the larvae were distributed in three classes of larval duration (Ci:days): C1:<=10 (10.26%), C2:0 15 (64.10%), C3:>15 (25.64%). The most significant differences between the observed and expected frequencies of larvae in C1, C2 and C3 occurred in T2 (50.00%), T1 (30.67%) and T1 (3.33%), respectively. Treatment 1 (T1) presented 95.83% of the larvae in C2 and 0 in C1 whereas the largest contribution to C1 was T2 (26.08%) and O by T1. The treatments which contributed the least to C3 class were T1 and T2. The mean larval duration in T4 (13.87±1.512A) and T0 (13.70±2.176A) are similar and longer than in T2(11.65±2.308B) whereas those of T1 (12.62±1.055AB) and T3 (12.77±2.287AB) are among those. The results suggest that, at a certain concentration, the EMeC is bioactive, accelerating the larval cycle of S. frugiperda, because T1 and T2 tend to shorten (C1) and to center (C2) over the larval period, respectively, whereas T4 showed no equating effect for T0.

Keywords: Anemopaegma arvense, Spodoptera frugiperda, biocidal effect