Black leg of seedlings

roots rot and very little of the root system survives. On the border between air and soil or substrate the plant turns brown. A typical symptom of a Pythium [...] water, too high or low temperatures or sudden fluctuations in temperature. Pythium ultimum mostly occurs at low soil or water temperatures and causes among [...] with a finger nail. Life cycle and appearance of Black leg of seedlings Pythium belongs to the Oomycetes, a separate group of microorganisms and is therefore

Fusarium spp.

as wilting, stunting and chlorosis or lesions on the stem and/or leaves. Life cycle and appearance of Fusarium spp. Fusarium is a group of soil-borne fungi [...] is a complex of many species, who collectively have a very broad host range. F. solani causes foot and/or root rot of the infected host plant, and the [...] Fusarium sambucinum (a.k.a. F. sulphureum ) causes dry rot of potato. The rot is dark and wet at first. The lesions are irregular and sharp-edged. In cavities

Damping-off

roots rot and very little of the root system survives. On the border between air and soil or substrate the plant turns brown. A typical symptom of a Pythium [...] cortex with a finger nail. Life cycle and appearance of Damping-off Pythium belongs to the Oomycetes, a separate group of microorganisms and is therefore [...] General Pythium is considered a ‘weak pathogen’, meaning that it can usually only affect plants that are in a sub-optimal condition or suffer from stress, caused

Tea spider mite

the veins and midrib and gradually spreads to entire leaf. Youngs leaves are also equally affected. Infested leaves become reddish bronze and spider mite [...] transpiration and moisture loss. Absence of shade, high temperature and dry conditions are congenial conditions for pest outbreak. Life cycle and appearance [...] loss. Damage symptoms Larvae, nymphs and adults causes damage to the tea plant which sucks the sap of leaves and occasionally on petioles. Red spider mite

Angular leaf spot

of the crown can be infected, creating a look similar to that of a Phytophthora fragariae infection. Life cycle and appearance of Angular leaf spot Xanthomonas [...] from the lesions on the leaves and form a secondary source of infection. They are dispersed by rain, irrigation water or handling of the plants. Infection [...] happens both passively and actively. Infection and disease development are favoured by temperatures around 20 °C during the day and cold nights, in combination

Black sigatoka disease

size and turn brown with light grey centres. These spots enlarge further and the tissue around the lesions turns yellow and dies. Lesions merge and the [...] light yellow spots or streaks on leaves of about one month old. The symptoms run parallel to the veins. Within a few days, the spots become a few centimetres [...] hyphae emerge from the stomata and either develop into conidiophores with new conidia or grow across the surface and infect adjacent stomata. Both types

Apple collar rot

between 15 and 23 °C and higher water content than is optimal for crop growth. Phytophthora overwinters in roots, infected tubers and bulbs or in the soil [...] germination and attract the zoospores. The pathogen grows into the stem and on the plant surface and new sporangiophores (structures containing sporangia, a type [...] ting and be careful with overhead irrigation since both a high water content of the soil and water splash promote disease. Ensure fast drying and wound

Phytophthora blight

germination and attract the zoospores. The pathogen grows into the stem and on the plant surface and new sporangiophores (structures containing sporangia, a type [...] ting and be careful with overhead irrigation since both a high water content of the soil and water splash promote disease. Ensure fast drying and wound [...] leaves and fruits. Late blight or Phytophthora blight (Phytophtora infestans f.sp. infestans ) causes water-soaked lesions with vague borders and white

Verticillium wilt

Start with clean soil or substrate by heating it at a temperature if at least 65 o C for a minimum of 30 minutes Use clean seed, tubers or cuttings Grow less [...] erticillium albo-atrum and Verticillium dahlia e are the most important plant pathogens. Verticillium dahlia causes verticillium wilt and early dying of potato [...] of the plant. Cutting the stalk horizontally reveals a slight discolouration of the vessels, brown or greenish, but much less distinct than the discolouration

Cutworms

Life cycle and appearance of Cutworms The adults of Agrotis spp. have pale grey to grey-brown forewings with a faint kidney-shaped marking and a red spot [...] broad hindwings, evenly light or dark grey or orange-yellow with a broad dark marginal stripe. The wingspan is about 40-55 mm and the dorsal thorax is covered [...] separately or in batches on the ground, or on the plant close to ground level. The larvae are yellowish when hatching with a dark head capsule and prothoracic