HORTICULTURE

Detailed explanation-1: -Examples of obligate parasites are the downy mildews, the powdery mildews, and the rusts. Certain fungi form highly specialized parasitic relationships with insects. For example, the fungal genus Septobasidium is parasitic on scale insects (order Homoptera) that feed on trees.

Detailed explanation-2: -Nematodes – also known as roundworms – exist in almost every environment and survive as parasites on human, animal or plant hosts. Plant-parasitic nematodes can devastate agricultural crops by interfering with roots; the annual economic loss from such pests is estimated at more than $100 billion.