Abstract:
Onion thrips, Thrips tabaci (Thysanoptera: Thripidae) is a major insect pest constraining onion production in the North Eastern Ethiopia. Therefore, field experiment was conducted at Gedo Ber small-scale irrigation scheme in Gubalafto district of Northeastern Ethiopia during the 2020/21 irrigation season. The experimental treatments were onion varieties namely: Bombay Red, Adama Red and Nafis were used as main plot treatments and intercropping onion with other vegetables including, Roma VF, Nantes and Black seed, as subplot treatments. The experiment was laid out in a randomized complete block design (RCBD) with split plot arrangement and replicated three times. The experimental plot size was 3.8m x 1.5m=5.7 m2, spacing between plots and blocks was 0.5m and 1m, respectively. Data was collected to observe the number of banded onions thrips were recorded from ten randomly sampled tag onion plants in the entire plot at 15, 30, 45, 60, 75, 90 and 105 days after transplanting. Results showed that intercropping Nafis with Nantes and Bombay red with Roma VF significantly reduced onion thrips population by 71.14% and 54.61% respectively. Similarly, intercropping Nafis with Nantes had highly significantly showed a better effect in reducing thrips damage severity by 28.03% ,at higher infestations. The intercropping onion varieties with vegetable treatments significantly reduced onion thrips per plant compared to sole cropping. The highest marketable onion yield (40.13 t/ha) was obtained from intercropped Nafis with Nantes. The lowest (24.56 t/ha) was obtained from solo cropping of Adama red. Intercropped Nafis with Nantes gave the highest gross income (708768 ETB/ha). The lowest gross income was recorded from the solo cropped treated plot of Adama red (267446 ETB/ha). The study clearly showed that intercropping onion with other vegetables reduced the number of onion thrips and their damage on onion in the study area and hence can form an integral component in the integrated management of thrips on onion.