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 [...] hampered. Life cycle and appearance of Black sigatoka disease Black sigatoka ( Mycosphaerella fijiensis ) produces both ascospores and conidia. The ascospores [...] lla fijiensis also known as black sigatoka, is an ascomycete fungus that causes leaf-spot of banana. Damage symptoms Black sigatoka (Mycosphaerella fijiensis

Black leg of seedlings

finger nail. Life cycle and appearance of Black leg of seedlings Pythium belongs to the Oomycetes, a separate group of microorganisms and is therefore not a [...] flower buds fall off. The side roots rot and very little of the root system survives. On the border between air and soil or substrate the plant turns brown [...] immediately after planting. Avoid cold and excessive warm irrigation water. Keep the water content of the substrate below 70% and ensure good drainage Disinfect

Black rot of carrots

both direct and through wounds and stomata. Spores are dispersed by wind and in some species through the splash of rain. How to prevent Black rot of carrots [...] Alternaria species is the asexual stage. Conidia and mycelium overwinter in the soil and on crop residues and cause primary infection of the leaves. Survival [...] dry, sunken, black lesions. Typically, Alternaria causes spots on leaves, petals and stems. These spots can be distinguished by the dark and brown concentric

Black root rot of cucurbits

cucurbits. Life cycle and appearance of Black root rot of cucurbits Phomopsis sclerotioides survives in the soil and is a strong saprophytic competitor, which [...] are slightly sunken and are mostly formed around the point of attachment of lateral roots and root hairs. The lesions may grow and encircle the root. The [...] The roots become yellow-brown to black and ultimately die. Black lesions with fruiting bodies occur more commonly at temperatures of approximately 20 °C

Mealybugs and scales

wingless and immobile, and covered with a hard scale (armoured scales and soft scales) or with waxy threads (mealybugs). They suck the sap of plants and are [...] mealybugs and soft scales also produce honeydew (on which moulds grow) resulting in considerable damage in ornamental and fruit crops and loss of value [...] the crop in various ways: nymphs and females extract the sap from the plant, stunting growth and causing deformation and/or yellowing of leaves, sometimes

Wheat bunt

They rupture at harvest and release black, powdery spores, that smell like fish, hence the common name stinking bunt. Life cycle and appearance of Wheat bunt [...] General Tilletia tritici and Tilletia laevis only differ in one gene and easily hybridize. There is debate whether they should indeed be considered separate [...] Tilletia tritici and Tilletia laevis survive as teliospores in the soil or on seed. These teliospores germinate in response to moisture and form basidiospores

Green peach aphid

making the crop and its fruit sticky. Black fungal moulds ( Cladosporium spp.) grow on this honeydew, contaminating fruit and ornamental crops and rendering [...] have a brown-black head and thorax and a yellow-green to green or even reddish abdomen. They have a dark brown spot on the abdomen and several transverse [...] least 100 different viruses and is thus rightfully feared by many growers. Nymphs and adults extract nutrients from the plant and disturb the balance of growth

Cottony cushion scale

red-brown body colour and covering of granular, white wax. The legs, antennae and body hairs are conspicuously black. The nymphs and adult females produce [...] spp ., Casuarina spp . and Pittosporum spp ., but it can damage many types of fruit and forest trees, and ornamental shrubs and trees. Damage is mostly [...] stages. Immature cottony cushion scales have black limbs and an orange-brown body that is coated with white and yellow wax. The adult ‘females’ are easily

Tea mosquito bug

torched by fire. Life cycle and appearance Adult is slender 6 - 8mm long, black colour with red thorax, black and white abdomen and greenish brown wings. Females [...] punctured snot to dry and die, curling of leaves, badly deformed and eventually fall off. The infested shoot also shows same such spots and subsequently drying [...] Helopeltis antonii attack cashew nut guava, neem and tea. Damage symptoms Helopeltis is a sucking pest. Nymphs and adults are damaging stages which suck the sap

Cotton bollworm

stop growing, mature rapidly, and drop off. In legumes, flowers are attacked, and seed pods may be pierced. Life cycle and appearance of Cotton bollworm [...] mm in length and have a wingspan of about 40 mm. The grey-green males are smaller. The forewings are edged with a line of black spots, and the hindwings [...] almost spherical with a flattened base and a diameter of about 0.5 mm. They are at first a shiny yellowish white, with their colour changing to brown just