Abstract :
A. glycine soybean infestation caused yield loss reaching 58%. Environmentally
friendly controls using vegetable ingredients will maintain environmental quality. This
study was conducted to determine effectiveness of combined of gadung tuber and grass
grinting extracts on soybean virus (A. glycine) vector pests and to know the mechanism of
toxicity to these pests.
The research was conducted from June to September 2018. The research began
with extracting of gadung tuber and grinting, phytochemical screenning, preparation of
soybean plants, rearing and collection of aphids, investment in aphids, in vitro testing
and in vivo tests on bioassays. The effectiveness test of the application uses a simple
Randomized Block Design (RBD). Variation analysis at 5% level, and Duncan's Multiple
Range Test (DMRT) test. Calculations of LC50 and LT50 use probit regression analysis.
The results showed that the highest compounds contained in gadung tubers were
alkaloids, whereas in grinting grasses were saponins. Both of these compounds have the
potential as a base for vegetable insecticides. The percentage of A. glycine mortality in
P2 (Positive Control), P3 (1: 0) and P7 (3: 2) treatments was calculated from
observations in the 60th minute, while treatment P4 (0: 1), P5 (1: 3) and P8 (3: 1) began
to have A. glycine mortality in the 180th minute. Meanwhile, other combination
treatments showed A. glycine mortality rates at 360 minutes. The combination treatment
of gadung extract and grinting 3: 2 (v / v) (P7) and 3: 1 (P8) showed the most effective
results compared to positive controls and other treatments with mortality mean values at
all observations of 87.44% and 86, 7%. The LC50 value of gadung extract at the first
observation was 3%, the grinting extract was 3.08%. The lowest LT50 value is in
treatment P7 (3: 2) with a time of 3.88 hours. a combination of gadung extract and
grinting can suppress A.glycine infestation and potentially a plant-based insecticide.