Explanation:

Justification: Statement 1: Citrus canker can be a serious disease where rainfall and warm temperatures are frequent during periods of shoot emergence and early fruit development. It is caused by the bacterium Xanthomonas axonopodis. Transmission mode is air.

Statement 2: Wheat leaf rust is a fungal disease that affects wheat, barley and rye stems, leaves and grains. In temperate zones it is destructive on winter wheat because the pathogen overwinters (wait out the winter season).  Infections can lead up to 20% yield loss exacerbated by dying leaves which fertilize the fungus.

Statement 3: Bhendi yellow vein mosaic was first reported in okra plats in 1924 in India and Sri Lanka. The symptoms include alternate green and yellow patches. It is caused by a VIRUS and mode of transmission is via insects.