Transcript Plant Protection Practices in TPS Nursery I

Introduction
• Potato cultivation can be a profitable enterprise when a few basic
precautions are taken.
• Selection of healthy and disease free planting material is an
important step to avoid diseases in potato nursery. Certified seeds
must be used as planting material.
• Diseases such as bacterial wilt, fungal wilt, powdery mildew, early
blight, etc are common diseases found in potato nursery.
Bacterial Wilt
Symptoms: Initial wilting of leaves accompanied by mild yellowing
may affect only one side of the leaf. Later severe wilting, browning,
desiccation of leaves and death of seedling occur. Vascular strands
darken and grayish white slime exudes in cross section. Wilt disease
develops rapidly at high temperatures.
Control: Crop rotation with cereals and legumes, use of disease free
seeds, crop sanitation, tuber dipping with 0.5% Aretan or Agallol
suspension for ten minutes and soil treatment with Brassicol @ 20-30
kg/ha manage the disease at low level. A combination of seed and
soil treatment gives the best control of diseases in potato.
Powdery Mildew of Potato
Symptoms: Initially, infected leaves or
stem exhibits whitish spore masses
resembling like soil residues, dust or
spray deposits.
Infection of Powdery Mildew on Potato
Leaf
Management:
In
severe
infection,
spraying of sulfur formulations at 15
days interval through three sprays of
fungicides like 0.2% Wettable Sulfur,
0.1% Tridemorph or 0.1% Dinocap is
recommended.
Infection of Powdery Mildew on Potato
Leaf
Verticillium Wilt of Potato:
Symptoms: Disease occurs in tropical,
subtropical climatic regions. Yellowing of
basal leaves follows wilting of plant.
Vascular system of lower stem turns
brown. Disease causing fungi survives in
Unilateral Leaf Necrosis And Wilt in
Potato
soil, plant debris and on host plants.
Management: Follow Crop rotations with
legumes, use disease resistant varieties,
timely irrigation and foliar application of
Benlate (0.1%) is effective.
Vascular Discoloration of Potato Stem
(Top) Non-affected Stem (Bottom).
Potato Leaf Roll Virus (PLRV)
Symptoms: Disease is transmitted by
aphids. Upper leaves roll towards base,
rolls are stiff, leathery and under side
becomes
tinged
purple.
Plants
are
stunted and erect. Upper leaves are pale.
Infected Potato Plant by PLRV
Crop yield losses may reach up to 90%.
Management: Select healthy plants from nursery, eliminate
diseased plants through rouging. Spraying systemic insecticides
decrease vector (aphid) infestation and disease spread. PLRV
can be effectively eliminated from tubers by heat treatment.
Potato Viruses Y and A (PVY and PVA)
Symptoms: These viruses are transmitted
through aphids. bunching, twisting of leaves,
downward turning of leaflet margins, stunting,
necrosis of veins, necrotic spotting, leaf
necrosis
and
stem
streaks
are
typical
PVA Infected Leaf of Potato
symptoms. The yield reduces up to 80%.
Management: PVY and PVA diseases are
controlled by elimination of aphid infestation,
clonal selection of seedlings, rouging of
PVY Infected Leaf of Potato
diseased seedlings, use of resistant cultivars.
Cyst Nematodes
Symptoms: Stunting, yellowing and
early maturing of leaves. White/yellow
spherical female nematode (0.5-1.0 mm
diameter) seen on potato roots. They
turn into brown cysts containing eggs
persisting for several years. Cysts are
Cyst Nematodes on Potato Roots
carried by soil sticking to tubers, farm
machinery, tools and containers.
Management:
Use
of
nematode
Resistant varieties, long crop rotation,
high doses of organic matter. Use of
Nematicides and soil fumigants.
Symptoms on Potato Leaves