Yellow Margined Leaf Beetle – Microtheca ochroloma

Yellow Margined Leaf Beetle – Microtheca ochroloma Scientific Name: Microtheca ochroloma Common Name: Yellow Margined Leaf Beetle Distribution: The native of South America, the yellowmargined leaf beetle may be found outside of the US in Argentina, Brazil, Chile, and Uruguay. Host plants: This species’ typical hosts are all members of the Brassicaceae plant family. Broccoli, cabbage, cauliflower, collards, mustard, radish, turnip, and watercress are among the damaged vegetable harvests. In some parts of Florida, watercress is a significant crop. The majority of the output is frozen and distributed throughout Canada and the eastern United States. A specific issue with mustard and Chinese cabbage is the yellowmargined leaf beetle, particularly for organic gardeners. Identification: The tall, vivid orange egg is deposited on plant stems, behind leaves that have fallen, or on the soil’s surface alone or in small groups. It takes four to five days for an egg to develop. The larva has a dark, sclerotized head capsule that is either brown or black. It is grayish to yellow-brown in color and coated in a thin covering of hairs. Before pupating, the adult larva forms an odd, blackish network around itself. The pupal case’s black hue contrasts sharply with the green foliage as it is affixed to the undersides of leaves. Five to six days pass during the pupal stage. Before emerging, new adults spend around two days in the pupal case. The mature beetle is often dark brown, copper, or black in color and is around 5 mm in length. The popular name of this species comes from the markings on the elytra’s borders, which are either brown or yellow in color. There are four rows of deep punctures on each elytron. Two lobes make up the third tarsal segment. Life Cycle: The beetle may finish its life cycle in less than a month if the right circumstances are met. After emerging from the pupae, adults can begin copulating six days later, and females can deposit eggs three to six days after that. Adults in Florida stay active all winter long.  Mild Gulf Coast winters may produce more than one generation annually. Damage: In the spring, when the adults and larvae are seen eating on crucifers, the most of the harm is done. They create tiny holes in the leaves and leaf edges where they feed, frequently defoliating the host. Larvae strip individual stems in groups, especially in the early instars. This is frequently an issue limited to residential or small gardening. In South American fields, it was a commercial pest prior to the application of contemporary pesticides. Management: For the normal farmer, the yellowmargined leaf beetle poses minimal threat since foliar pesticides that target other insect pests often manage it. However, some homes opt not to use pesticides, and organic crops have challenges since they are unable to utilize these products.  In mizuna field experiments, beetle populations were greater on plants in the middle of the field than on the edges. Furthermore, organic farmers did not seem to find intercropping to be a helpful management strategy against this pest when it came to mizuna.