Peanut yellow spot

The initial signs of infection appear as chlorotic spots on young leaves, which gradually develop a distinctive bright yellow coloration.

As the virus systemic infection progresses, leaves exhibit significant deformation, including leaf curling and a stunted, crinkled appearance.

Advanced stages of the disease are characterized by the development of necrotic ring spots and stripes on the foliage, indicative of severe vascular damage.

Infected plants display a noticeable reduction in size, with shortened internodes and a bushy habit compared to healthy specimens.

In the reproductive stage, the virus causes flower abscission and significant pod development failure, leading to a drastic reduction in yield potential.

Peanut yellow spot is a systemic viral disease caused by a virus belonging to the orthotospovirus genus, specifically Orthotospovirus arachiflavamaculae.

As an obligate parasite, this virus cannot survive in soil or dead organic matter for long, requiring a living host to perpetuate its lifecycle.

Weeds growing in or around peanut fields act as the primary viral reservoir, sustaining the pathogen during off-season periods.

The spread of the virus across fields occurs primarily through biological vectors, as the virus particles are transmitted by sap-sucking insects.

The disease biology is closely linked to the population dynamics of thrips, which acquire the virus while feeding on infected plant tissues and pass it to healthy plants.

The development and severity of the disease are highly dependent on the density of the thrips population within the field environment.

Warm and dry weather conditions are particularly favorable for the disease as they accelerate the reproduction and migration cycles of the insect vectors.

The migration of adult thrips from nearby weed-infested areas into peanut fields creates localized outbreaks that can quickly spread throughout the entire crop.

Monocropping and poor field sanitation facilitate the accumulation of both the virus and its insect vectors over multiple growing seasons.

Environmental stress factors, such as drought or nutritional imbalances, increase plant susceptibility and exacerbate the viral infection process.

The primary economic impact of peanut yellow spot is the substantial reduction in photosynthetic capacity, causing overall plant vigor to decline rapidly.

Infected crops show delayed and uneven pod maturation, which makes timely harvesting difficult and results in high percentages of unfilled or shriveled pods.

Yield losses can be severe, with potential reductions of up to 40–60% depending on the timing of the initial infection and the overall pressure of the insect vectors.

Seed quality is negatively affected, with infected plants often producing seeds with poor germination rates and reduced vigor for the following season.

Additional costs incurred by farmers include repeated insecticide applications and the loss of market value due to damaged and low-quality kernels.

The cornerstone of disease management is strict field sanitation, including the removal of potential weed hosts that harbor the virus during the off-season.

Targeted use of systemic insecticides to manage thrips populations is essential to reduce the transmission rate of the virus during early plant growth stages.

Cultivation of resistant or tolerant peanut varieties offers the most sustainable and cost-effective approach to managing the disease in endemic areas.

Maintaining proper spatial isolation between new peanut plantings and older fields helps prevent the movement of insect vectors from infected areas.

Monitoring thrips populations with sticky traps allows for early detection, enabling farmers to intervene with control measures before the virus spreads widely.