Black sigatoka disease

conidia. The ascospores are wind-dispersed over longer distances, the conidia are splash-dispersed within the crop. Both types of spores cause the exact same [...] discharged from the lower leaves in the stack Use under-canopy (drip) irrigation to reduce splash dispersal Lower the humidity as much as possible by [...] 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 in size and turn

Aphidius ervi

is available in a bottle ( Ervipar ). Spread the material on rock wool slabs or in Diboxes Make sure the material remains dry and is not moved from its [...] ervi is a very dark aphid parasitoid. The waist is entirely black, without striping. As it can develop in large aphid species they are generally much larger [...] Myzus spp. is their host, they will be of the same size. The parasitization behaviour resembles Aphidius colemani , however, Aphidius ervi is more aggressive

Cotton aphid

from the plant and disturb the balance of growth hormones. As a result, the plant’s growth is retarded giving rise to deformed leaves or, if the infestation [...] as chrysanthemum and kalanchoe. The cotton aphid ( Aphis gossypii ) is distributed throughout the world but prefers the warmer regions. It has been a pest [...] skin, betraying their presence in the crop. The cotton aphid can be distinguished from other aphids by the colour of the two cornicles (siphunculi). These

Verticillium wilt

new hosts. In the senescent tissue, the resting mycelium or the microsclerotia are formed. The spread of the fungus by mycelium growth is limited. Dispersal [...] vessels. The presence of both the fungus and the gum causes the xylem vessels to get blocked, which in turn causes the plant to wilt. Spores may be wind-dispersed [...] cause wilting of plants. The wilting starts at the lower leaves. These leaves are pale-green, then orange-yellow. In the beginning the plant seems to recover

Black leg of seedlings

later the plants wilt irreversibly. In potted plants the flower buds fall off. The side roots rot and very little of the root system survives. On the border [...] and soil or substrate the plant turns brown. A typical symptom of a Pythium infection is the easy stripping of the skin from the root cortex with a finger [...] enable the spores to move through water. The zoospores are chemically drawn to the growing roots of young plants and move towards them through the soil water

Pierce's disease of grapevine

in the leaves to neighbouring peach trees with the bacteria mainly in the roots is much more successful than the other way around. In general, the low [...] along the margin or the tip from early to midsummer. The necrotic area spreads over the leaf from the margin and is marked by a chlorotic band. In the beginning [...] plums): In peach, the canopy of infected plants is compact and umbrella-like due to the shorter internodes. The foliage is denser and the leaves are a darker

Bacterial wilt, brown rot

s roots on the stem. The vascular stem tissue is coloured brown and when the stem is cut, bacterial slime oozes from the wound. This is the way to distinguish [...] . Race 3 is pretty much restricted to potato and tomato. Whereas other races have optimum temperatures of 35-37 °C, the optimum for Race 3 is 27 °C, which [...] vascular browning is common with bacterial slime oozing from the cut. When the bacteria transfers to young plants through infected tubers, the wilting and collapse

Damping-off

bulbs. At first, the plants recover during the night, but later the plants wilt irreversibly. In potted plants the flower buds fall off. The side roots rot [...] of the root system survives. On the border between air and soil or substrate the plant turns brown. A typical symptom of a Pythium infection is the easy [...] enable the spores to move through water. The zoospores are chemically drawn to the growing roots of young plants and move towards them through the soil water