AZEVEDO, A. I. B. A.; http://lattes.cnpq.br/7248658454730027; AZEVEDO, Aderdilânia Iane Barbosa de.
Résumé:
This work was developed with the aim of evaluating the oil bioactivity of neem seed on the
insect pests of stored seeds, Tribolium castaneum e Alphitobius diaperinus. To carry out the
bioassays, peanut seeds of the BRS Havana cultivar were treated with neem oil and kept on
trays during 24 hours period. Fifty grams of seeds were put in plastic recipients and infested
with insects in the adult phase. In the T castaneum bioassay the effect of neem oil
concentration of 0.0,0.5,1.0, 1.5 and 2.0% (mass/volume) on 10 not sexed insects maintained
in recipients measuring 6.0 cm height and 9.0 cm diameter was avaluated. For A diaperinus
the neem oil concentrations of 0.0, 1.0, 2.0, 3.0 and 4.0% (mass/volume) were tested on 20
not sexed insects maintained in recipients measuring 8.0 cm height and 11.0 cm diameter.
Both bioassays were designed with five treatments and four replications. The analyzed
variables were mortality, offspring number (larva, pupa end adults) and the number of
punched seeds, evaluated in four stored periods (30, 60, 90 and 120 days). For data analysis,
nonparametric tests were used. Friedman test (P<0.05) was used for variance analysis test and
Student Newman Keuls (P<0.05) for means comparison. The neem oil efficiency was
evaluated by Abbott method and the punched seeds percentage and the offspring number
fluctuations were represented in graphics. In the four evaluated periods T. castaneum obtained
mean values of mortality not higher than 37.5%, showing low product efficiency on the adult
insect mortality. The biology was enlarged due to T. castaneum feeding on treated neem seed.
In all studied period, the number of punched seeds in the control was inferior to each one of
the oil concentrations and the most efficient concentrations were of 1.0, 1.5 and 2.0%. The effect of the neem on the insect's biological development, the adult's reproduction, the
increase of the larval development phases and on the reduction of pupae and offspring adults*
number, during all the stored period, was also observed. For A. diaperinus, the product
efficiency on the insect mortality from 90 days of storing, with efficiency varying from 26,01
to 97,50%, was detected. The most efficiency neem concentrations were of 3.0 and 4.0% and
the insect mortality was possibly attributed to alimentary deterrence. According to the
offspring number, the neem oil made impossible larvae metamorphose, not allowing that the
A. diaperinus life history was completed. The control differed statistically of the neem oil
treatments to punched seeds number in all studied periods, verifying 100% of damage in the
control, except to 30 days period, with approximately 80%. In the oil treatments those
percentages varied from 2.7 to 12.9%. Through the offspring number it was verified that neem
oil affected all the development phases of A. diaperinus, promoting protection to peanut seeds
in all periods evaluated.
