Chickpea redleaf virus

The virus is characterized by its reliance on insect vectors for transmission. It does not spread mechanically through physical contact, contaminated tools, or infected seeds, which distinguishes it from many other plant-infecting viruses.

Transmission occurs exclusively through aphid vectors, most notably Acyrthosiphon pisum (pea aphid) and Aphis craccivora. Once an aphid ingests the virus by feeding on an infected plant, it retains the virus and remains infectious for its entire lifespan.

Reservoirs for the virus include perennial legumes and various wild weeds that survive through the winter. These plants serve as the initial source of inoculum, from which aphids migrate to young chickpea seedlings during the growing season.

The spread of the virus is highly dependent on environmental conditions that favor aphid population dynamics. Mild temperatures and adequate moisture promote the reproduction and migration of the aphid vectors, significantly increasing the probability of a localized epidemic.

Infection by CpRLV leads to severe stunting of chickpea (Cicer arietinum) plants. The physiological stress caused by the virus prevents the plant from developing its full canopy, leading to a thin, unproductive crop stand.

Photosynthetic activity is significantly impaired in infected plants. This metabolic disturbance results in reduced biomass production, early senescence, and a general decline in the plant's structural integrity.

The most direct impact is on yield quantity and quality. Infected plants produce fewer pods, and the seeds within are often shriveled, small, and of poor nutritional value, rendering them unsuitable for high-quality food markets.

Early-season infection is particularly devastating, as it stunts the plant at a critical developmental stage, preventing effective nodulation and subsequent nitrogen fixation. This exacerbates the nutrient deficiency in the plant.

In cases of high disease pressure, the cumulative damage across a field can reach critical levels, resulting in significant financial losses for producers who are forced to manage stunted and poorly yielding crops.

The characteristic symptoms of CpRLV include a pronounced reddish or orange discoloration of the leaves. This symptom typically begins at the upper canopy and spreads downwards as the infection progresses throughout the plant.

Affected plants exhibit severe dwarfing, with significantly shortened internodes. The leaves often curl downwards, become brittle to the touch, and may eventually develop necrotic spots as the tissues die prematurely.

A reduction in the root system's vigor is commonly observed, which limits the plant's ability to uptake water and essential minerals. This makes the plant particularly susceptible to secondary stress from drought or nutrient imbalance.

Reproductive success is severely hampered. Flowering is delayed or reduced, and the few flowers that do develop often fail to set pods, leading to significant abscission of floral buds and young pods.

• Reddish or orange leaf discoloration.
• Extreme stunting and reduced plant height.
• Downward curling and brittleness of leaves.
• Poor pod set and floral bud abscission.
• Systemic necrosis in later stages of infection.

Management of CpRLV focuses primarily on the suppression of aphid populations. Systemic insecticides are recommended to reduce the vector population, thereby limiting the rate of virus transmission within the field.

Cultural practices are essential for long-term control. Destroying weeds and volunteer legumes surrounding the planting area minimizes the initial inoculum source, depriving aphids of their winter host plants.

Selecting appropriate planting dates can help avoid the peak migration period of aphid vectors. In many regions, shifting the sowing window can allow plants to reach a more robust developmental stage before the onset of heavy aphid pressure.

Breeding for genetic resistance remains the most sustainable approach to managing the disease. Farmers are encouraged to use certified, disease-free seed and to prioritize varieties that show field tolerance to the virus.

Effective monitoring using yellow sticky traps allows growers to detect the arrival of aphids early in the season. This data-driven approach enables timely intervention, ensuring that insecticide applications are targeted and economically efficient.