Chives have been proven to repel many beetles including cucumber beetles and japanese beetles, carrot flies, some types of aphids, some fruit worms and cabbage worms. It is not a miracle plant and does not repel all insects, but to borrow and alter a quote from Lincoln: 'You can repel some of the bugs some the time and all of the bugs some of the time but you can't repel all of the bugs all of the time'
Footnotes and References
1. Allelopathic Suppression of Pseudomonas solanacearum Infection of Tomato (Lycopersicon esculentum) in a Tomato-Chinese Chive (Allium tuberosum) Intercropping System
2. Effects of genotype and intercropping with Chinese chives (Allium tuberosum) on Fusarium wilt tropical race 4 in banana
3. Evaluating Companion Planting and Non-host Masking Odors for Protecting Roses from the Japanese Beetle
4 Olfactory response of Myzus persicae (Homoptera: Aphididae) to volatiles from leek and chive: Potential for intercropping with sweet pepper