The cultivation of Carrot- Pests and Diseases

PEST OF CARROT FLY: The mature adults have a brown head and abdomen is black and elongated. The larva is white to bright yellow. In winter the puparium enter in the soil and emerge in spring. This insect lays its eggs in the ground, ten to twelve days post, larvae emerge that penetrate the interior of the root, where practice winding galleries, especially on the outside, which will later be home to rotting.

APHIDS: The biting lice feed on the skin of the leaves so heavily that the leaves curl and take on a yellowish color. There are many predators of aphids such as ‘Coccinella septempunctata’, ‘Chrysoperla’ and some parasitic ‘hymenopterans’ that develop the larvae inside the aphid.

GRAY WORMS: The caterpillars devour the aerial parts of plants during the night, and during the day remain in the soil or under leaves.

WIREWORM: They attack the roots of carrot producing galleries that sometimes generate rotting.

NEMATODES (Heterodera carotae, Meloidogyne spp.): * Heterodera carotae is a very important and widespread pest in temperate climates. The results of its attack are very small plants with foliage and reddish leaves. The roots are reduced and are branching. * Meloidogyne spp. spreads in warm climates, producing significant damage to the roots, turning them into strings of guts. One method that is effective against this pest, and is used both in nurseries and in greenhouses, is to treat the soil with very hot water, because the nematodes are killed at temperatures of 40-50ºC.

DISEASES: MILDEW: As a preventive measure, it is recommended to use fungicides at the beginning of the first symptoms of the disease. Under normal conditions the frequency should be every 12-15 days. If it rains during the interval between treatments, another spray should be applied immediately after the rains.

POWDERY MILDEW: The attacks produced by both fungi are similar, and are characterized by the formation of a type of white rot and dirt formed by conidiophores and conidia, on the surface of the leaves.

CHOPPING OR CAVITY SPOT: It is one of the most problematic diseases in the cultivation of carrot. Damages are characterized by the following patches and are small and translucent with elliptical contours which are delineated. These stains rapidly evolve to light brown depressions, causing a collapse and darkening of the beds of superficial cells. Preventive measures are based on designing a proper drainage system and avoiding heavy soils and by crop rotations and nitrogen fertilization methods.

BURN THE SHEETS: The disease appears during the summer and autumn, during hot and humid environments. The first symptoms are presented in the form of small brownish spots, halos and yellowness spread across the edge of the leaves. The place where the spots die makes the leaves look like burned fabrics, especially where the leaflets have dried completely. The plant appears to be sunburned or treated badly. The fungus can cause very significant question of ‘nascencia’ which is carried by the seeds and later, cankers on the main root.