2. Wheat
• Wheat is a major cereal crop being grown in a variety of environmental
conditions and geographical regions with a variety of production strategies.
• It is one of the most important agricultural crops being grown on 9 million
hectares of land by 80% of farmers.
• It is a global commodity which accounts for roughly 19% of the world's
major grain crop production.
• In Pakistan, 38.5% of the labor force is employed in agriculture, which
contributes 19.2% to the country's GDP.
• Nearly 70% of the population depends on agriculture for their livelihood.
• Pakistan is the eighth-largest wheat-producing nation.
3. Wheat
• In terms of production and area, wheat is Pakistan's main source of food as
well as it delivers fundamental food diet to people.
• Wheat accounts for 37.1 % of the crop region, 65 % of the food grain
acreage, as well as 70 % of the production.
• Wheat was grown on 8,976 thousand hectares in crop year 2021-22 and
produced 26.394 million tonnes that is 3.9% lower than the previous year
production.
• There are several reasons of lower production including decrease in the
cultivated area, shortage of water at the sowing time, less use of fertilizers,
and high temperature during the month of March and April.
• Besides this, there are several diseases that attack wheat and lower its
production.
• Among these, wheat rusts significantly reduced the wheat production.
4. Stripe/ Yellow rust
• Puccinia striiformis f. sp. tritici is responsible of causing stripe/ yellow rust.
• This disease is found all over the world where wheat is grown.
• Wheat yellow rust impacts 88% of global wheat output, resulting in yearly
losses of around 5 million tonnes.
• Around 88 percent of the world's wheat varieties are susceptible and the
disease causes annual losses of almost US$ 1 billion worldwide.
• Yellow rust was prevalent in Rawalpindi, Faisalabad, Islamabad, Fateh
Jang, Chakwal, Hasan Abdal etc. during previous years.
• The disease did not show significant losses in Southern Punjab as the
environmental conditions were not very much favourable for pathogen
development.
5. Symptoms
• The disease primarily occurs on leaves, although glumes and awns
may also be affected.
• Stripe rust typically produces yellow or orange blister-like pustules
that are arranged in stripes.
• The lesions produce massive amounts of spores that are easily
dislodged and dispersed by wind.
• The spores may leave orange dust on the clothing of individuals
walking through heavily infected fields.
6. Epidemiology
• Stripe rust appears earlier in the season because development is
enhanced by the cool, moist weather early in the growing season.
• If the pathogen attack severely then losses may reach up to 70%.
• The pathogen requires 10-20℃ temperature with six to eight hours of
leaf moisture for development.
7. Brown/ Leaf rust
• The most prevalent rust throughout the world is wheat leaf rust
generally known as brown rust.
• Leaf rust is a main problem in cereal cultivated areas in the world.
• Leaf rust can cause reduction in yield ranging 10% to 40%, leading
to economic losses.
• This disease is usually appeared in all districts of Punjab wherever
wheat is grown and resulted in a significant yield losses.
• The casual organism is an obligatory parasite that can only produce
infectious urediniospores on living leaf tissue.
8. Brown/ Leaf rust
• To complete its life cycle, leaf rust needs both primary and secondary
hosts.
• Bread wheat and triticale are the major hosts whereas Thalictrum
speciosissimum and Isopyrum fumaroides are secondary host.
• Leaf rust develops in five stages, three stages on cereal plants and
two on alternate hosts because it is a macrocyclic fungus.
9. Symptoms
• Dusty, reddish-orange to reddish-brown fruiting bodies that appear on the leaf surface.
• These lesions produce numerous spores, which can cover nearly the entire upper leaf
surface.
• Leaf rust causes the most damage when severe rusting covers the upper leaves before
flowering.
• Early defoliation can occur, reducing time for grain fill and leading to the creation of
smaller kernels.
• Grain shrivels, and any nutrients produced – primarily in the flag leaf – are used by the
fungal infection instead of being transported to the grain.
• Early infection can result in weak plants and poor root and tiller development.
• Flag leaf infections results in huge yield losses that may rise up to 50%. Cereal crop
leaves, stems, and glumes are all affected by the rust disease.
• In case of epidemic, the disease attack on susceptible varieties and reduce the yield.
• The disease usually appears in the mid-February.
10. Epidemiology
• The ideal environmental conditions for development of infection are
temperatures ranging from 20-25 ℃ and at least six hours of moisture
on the leaf surface.
• With wet weather and ideal temperatures, lesions are formed within
seven to 10 days of infection, and spore production repeats another
disease cycle.
11. Black/ Stem Rust Symptoms
• Stem rust occurs when raised spots (pustules) form on stems and leaf
sheaths, although occasionally they may form on awns, glumes and seeds.
• Stem rust spots appear elliptical and differ from leaf and stripe rust in that
they are more elongated.
• The spots form on both lower and upper leaf surfaces and look orange to
dark-red in color.
• The margins on stem rust spots are ragged.
• Young pustules release numerous spores.
• Later in the growing season, spores transform and become dark colored,
hence the common name of black rust.
12. Epidemiology
• Stem rust development requires the warmest temperatures of the three
wheat rusts –ideally 20-35 ℃ and six to eight hours of moisture on the leaf
surface.
• With wet weather and optimal temperatures, new lesions are formed in
seven to 10 days.
• Stem rust disease also spreads spores through wind dispersal and splashing
water.
• Spores are produced in multiple cycles during the growing season.
• The disease spreads rapidly and can travel long distances by wind or other
means of transportation such as farm equipment or plant materials.
• While stem rust has historically been the most damaging disease of wheat,
it’s not as prevalent today thanks to resistant varieties.
13. Managing Wheat Rusts
• Farmers have several options to manage wheat rusts, including seed
treatments, variety selection, scouting, cultural practices and fungicide
applications.
• Moreover, use of fertilizers should be optimized as the application of
nitrogenous fertilizers in excessive quantity could be favorable for
disease development
14. Seed treatments
• Using the correct fungicide seed treatment and rate is one way to
provide effective and economical disease control in wheat production.
• Seed treatments protect seed and young plants from disease and other
threats to plant health and yield.
• Areas commonly infested with rust also will need a foliar fungicide
treatment to provide protection beyond the seedling growth stage.
15. Variety selection
• Where available, use rust-resistant varieties for best protection against
leaf rusts.
• Every commercially available wheat variety has a unique disease
package, and excellent disease resistance is not available to manage all
disease threats in high-yielding varieties.
• It’s best to select two or three high-yielding varieties that offer the best
resistance to common diseases found on your individual farm.
16. Scouting
• When scouting for weeds and insects, check for the presence of wheat
rusts.
• Monitor reports of wheat rust development that will allow you to track
the progression of rust diseases migrating from overwintering hosts
and will also help you predict the timing and severity of infestations
before they might affect your region.
• Keep a close eye on weather conditions because rust spores spread
through wind currents to promote disease infection.
17. Cultural practices
• Cultivation of disease resistant cultivars
• Good weed control preplant, at planting and throughout the growing
season also helps protect against disease and other pests.
• Sowing should be done in the month of November. Avoid early and
late sowing
• Removal of alternate host plants
• Avoid cultivation of varieties that have shown susceptibility in
previous years like
• Inqilab-91, Watan, Bhakkar-2002, Shafaq-2006, Sehar-2006, Galaxy-
2013, TD-1, and Gandum-1 etc.
18. Fungicides
• Good control of wheat rusts can be achieved with commercially available
fungicides and proper application timing.
• The decision to use fungicides should be based on scouting for symptoms.
• It’s important to assess disease severity from the onset of infection through
the various growth stages.
• Application timing should take into consideration that diseases should be
managed before infection reaches the upper leaves.
• Other factors affecting fungicide application are infection levels in the field,
the susceptibility of the variety and the market price for wheat grain.
