Black sigatoka disease

them, so the spores cannot be discharged from the lower leaves in the stack Use under-canopy (drip) irrigation to reduce splash dispersal Lower the humidity [...] 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 [...] 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

Bacterial spot

as they grow. The centre of the lesions may fall out as they become drier. Under humid conditions, the spots may merge with lesions on the petioles and [...] green fruits. The specks grow into brown spots that look like scab. These spots may be surrounded by a halo. In pepper, the spots on the leaves are also [...] also round and small to start with and slightly raised from the leaf surface. They occur on the abaxial (underside of) leaf surfaces and may enlarge into

Downy mildew of Cucurbits

For most downy mildews, the optimum temperature is around 15 o C and the closer the temperature is to this, the shorter the leaf wetness period that is [...] Inside the plant, the pathogens produce haustoria, small organs with which the pathogen can take up nutrients from the living plant cells. The pathogens [...] sporangia often germinate directly and the germ tubes infect the plants either through the stomata or directly by penetrating the cuticula. For germination free

Biological seed treatment

applied to the seed in a powder form or as a liquid. An even layer covers the whole seed. In this way, the beneficial ingredients are available to the seed [...] stress, the development of the root system, and the productivity of the crop. An overview of positive attributes of microbials depending on the organism: [...] colonize the roots and protect the crop during the entire growing season. Seed treatment increases the availability of plant nutrients in the root system

Grape downy mildew

instead of overhead irrigation to reduce leaf wetness. Ploughing to bury oospores in leaf litter and avoiding prolonged irrigation to prevent oospore germination [...] Veni GoKlean at the rate 1.25 to 1.5 ml per litre of water at 12-15 days intervals as preventative spray and or after recognition of the disease symptoms [...] grapevines with sexual overwintering and asexual cycles during the growing season. The pathogen overwinters as oospores in fallen, infected leaves. In

Cottony soft rot

base and the roots, whereas the ascospores infect the above-ground plant parts. In greenhouses, usually only mycelium is produced by the germinating sclerotia [...] sclerotia. The fungus grows quite rapidly inside the plant and kills the host cells. On the infected plant tissue white, fluffy mycelium occurs with new [...] new dark sclerotia. The fungus also infects seeds and tubers, thereby creating a source of infection for the next crop. The dispersal to neighbouring plants

Gummy stem blight

be recognized from the outside by the small narrowing of the tip of the mature fruits. The symptoms on stems, leaves and inside the fruits may occur together [...] brown lesions on the foot and higher up on the stem. On the lesions, golden-brown gummy drops occur, hence the name gummy stem blight. On the lesions, black [...] ascospores are the main source of dispersal of disease upwards in the crop and the conidia for spread of the disease downwards. How to prevent Gummy stem blight

Fusarium spp.

upwards. At the same time, the plant produces gum as a defence mechanism to stop the fungus from spreading. This gum blocks the xylem and causes the wilting [...] This species is the only Fusarium that actually grows inside the vascular system of the host plant and spreads upwards inside the plants. The other species [...] towards the foot of the plant and enters the vascular system. Inside the vessels, the fungus produces mycelium and many spores (microconidia), which are

Fusarium wilt

oxysporum is the only Fusarium that actually grows inside the vessel system of the host plant and spreads upwards inside the plants. The other species [...] Fusarium oxysporum is the species causing vascular wilt. First the leaves turn yellow and wilt, mostly on one side of the plant. Finally, the whole plant wilts [...] dispersed upwards on the outside of the plant. Most Fusarium species only make asexual spores. Some also produce ascospores. The Fusarium oxysporum life

Loose smut of barley

and the infected seeds are the primary source of inoculum in the next crop. The fungus survives inside the seed and when the seed germinates, the mycelium [...] mycelium of the fungus grows upwards inside the plant into the growing tip and the seed primordia. It only becomes visible after head emergence. The teliospores [...] They germinate within a day and infect the inner tissues of the newly infected seed. During maturation of the seed, the mycelium becomes thick-walled and swollen