Aphid Vectors Affecting Barley Yellow Dwarf Virus

The Barley Yellow Dwarf virus (BYDV in wheat) is part of the Luteal Viruses, forming one that includes five virus species closely linked. Different strains of BYDV differ in serological characteristics and their virulence, host range, and the specificity of their vectors. 

The virus particles are round. BYDV in wheat is carried by more than 20 different aphid species. The most prominent is the oat bird-cherry aphid and the aphid on corn leaf, the English grain aphid, as well as the green insect. Aphids contract BYDV by eating infected plants. They then transmit the virus to subsequent feeds.

List of aphids transmitting plant viruses

Aphids are tiny, sap-sucking insects that can have a significant impact on wheat crops by transmitting various diseases, notably the Barley Yellow Dwarf Virus control (BYDV) and Cereal Yellow Dwarf Virus (CYDV). These diseases are both detrimental to the health and productivity of wheat fields. Here’s a more detailed look at each:

1. Barley Yellow Dwarf Virus (BYDV in wheat):

   • Transmission: BYDV is transmitted by several aphid species. The most common vectors include the bird cherry-oat aphid (Rhopalosiphum padi) and the English grain aphid (Sitobion avenae), among others. These aphids damage in wheat causes the virus by feeding on infected plants and then transmitting it to healthy plants as they continue to feed.
   • BYDV Symptoms: Infected wheat plants show symptoms like stunting, yellowing of leaves (particularly at the tips), and sometimes red or purple discoloration. These symptoms usually appear first on the youngest leaves.
   • Impact: The disease can lead to considerable reductions in yield and grain quality. The severity of the impact often depends on the stage of the plant at the time of infection; earlier infections typically result in greater yield losses.

2. Cereal Yellow Dwarf Virus (CYDV):

   • Transmission: CYDV is transmitted in a manner similar to BYDV, with the same species of aphids acting as vectors. The virus is spread as aphids feed on the phloem sap of the plants.
   • Symptoms: Symptoms of CYDV are also similar to those of BYDV, including yellowing of leaves and stunting. However, CYDV symptoms can sometimes be milder compared to BYDV.
   • Impact: While the overall effects of CYDV might be slightly less severe than those of BYDV, the virus still compromises plant vigor and productivity, leading to reduced crop yields.

Disease Symptoms

Yellow dwarf symptoms in barley are variable and can be confused with grain streak mosaics, nutrient deficiency, or root diseases. Aphid vectors identify barley yellow dwarf, characterized by yellowed or stunted plants grouped in small patches among normal plants.

Leaf discoloration that is shades of red, yellow or purple starting from the tip down, and also from the midrib to the margin is common. The symptoms of wheat appear around the time of jointing. Barley yellow dwarf doesn’t create a distinct mosaic like the wheat streak mosaic, or the soil-borne mosaic. The slight yellowing that occurs on old leaf tips are normal. In cold temperatures, the tips can turn a reddish-purple. In times of high Aphid activity, the patches of BYDV-infected plants may be quite extensive in some areas.

Favourable Weather Conditions

Yellow dwarf of barley spreads through passive movement of winged aphid vectors during cold, dry seasons between 50-68°F temperatures. Wind support allows aphids to travel miles and spread the yellow dwarf disease further, even when their flight is restricted. Bright, sunny weather enhances disease symptoms, which typically appear about two weeks after infection, increasing disease visibility.In late summer, aphids migrate to early-planted winter wheat, but this migration usually stops in the fall season.

Aphid Control In Wheat

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Aphids are a major pest in wheat cultivation, capable of causing significant yield losses and transmitting diseases like Barley Yellow Dwarf Virus and Cereal Yellow Dwarf Virus. Effective aphid control in wheat is crucial for maintaining healthy crops and achieving optimal yields. Let’s explore some strategies, including the use of bioinsecticides such as BEVERIA WP, which is mentioned as an effective control measure against aphids.

• Cultural Practices

Controlling grassy weeds, including volunteer cereals in and near wheat fields, is a cultural method for managing yellow dwarf barley. Avoid planting small grains during midsummer and refrain from cover cropping or mixing with other crops in wheat areas. These methods will benefit reduce the spread of vector reservoirs and viruses in areas that grow wheat.

Seeding Dates

Genetic Resistance

A key strategy for managing BYDV is to cultivate resistant or cultivars that are tolerant. A high level of tolerance or resistance isn’t available in wheat. However, commercial cultivars vary in susceptibility to the yellow dwarf of barley. The excellent strategy is to plant a variety of wheat varieties in order to limit the possibility that one variety could be extremely susceptible to the illness. 

Chemical/Biological Control of BYDV

Continue reading to get the answer of how to control aphids organically. Fungicides are not effective against Barley Yellow Dwarf and shouldn’t be used to combat the disease. Seed treatments containing imidacloprid (Gaucho and various other products) or Thiamethoxam (Cruiser) will reduce the population of aphids through the autumn and, consequently, decrease the incidence of primary infections. However, together aphids control insecticides as seeds to fight Aphids might not be cost-effective due to the fact that aphids are sporadic infestations. Foliar insecticides in the fall can control aphids and reduce the likelihood of barley yellow dwarf infections in wheat. However, treatment may not be cost-effective if aphids escape or move into untreated areas, reducing the treatment’s effectiveness.

BEVERIA WP: A Bioinsecticide for Aphid Control

BEVERIA WP is an example of a bioinsecticide that can be employed in the management of aphids in wheat. It is based on naturally occurring organisms that target and control pest populations. Here’s how it works:

• Active Ingredient: BEVERIA WP typically contains a fungal strain or bacteria that are pathogenic to aphids. When applied, these organisms infect and kill the aphids without harming the plant or beneficial insects.
• Application: Users usually apply the product as a wettable powder, mixing it with water and spraying it directly onto the crops. The timing and frequency of application depend on the product specifications and the severity of the aphid infestation.
• Safety and Efficacy: Bioinsecticides like BEVERIA WP are considered safe for the environment and non-toxic to humans and animals. Other Integrated Pest Management (IPM) practices are compatible with these bioinsecticides, enhancing their effectiveness in agricultural settings. They offer a sustainable alternative to synthetic chemicals and help reduce the risk of pesticide resistance.

In summary, controlling aphids in wheat effectively requires a combination of strategies that balance immediate pest control needs with long-term sustainability. Products like BEVERIA WP enhance the range of tools available for farmers, allowing for effective management while supporting ecological health and crop safety.