Mustard Aphid
Lipaphis erysimi (?)
This aphid colony was found on new new growth of Sahara Mustard, Brassica tournifortii at Mequite Wash, Maricopa Co., Arizona on Feb 2, 2020.
Aphididae -- Aphid Family
Sahara Mustard, Brassica tournifortii, is an invasive weed that has become a major scourge in the Sonoran Desert. One reason it has become so pervasive is that it has escaped its natural enimies that tended to keep it in check in its native land. I have rarely found any insects feeding on Sahara Mustard.
Thus I was surprised and hopeful in finding this colony. If the aphid can become prevalent in the Sonoran Desert, there is hope that the weediness of Sahara Mustard will be reduced. Meanwhile agricultural researchers are searching for mustard varieties that are resistant to Lipaphis!