Jacquemontia mosaic

Symptoms typically include a distinct mosaic pattern characterized by yellow or pale green patches intermingled with normal green tissue.

Affected leaves often exhibit curling, crinkling, and a significant reduction in size, commonly referred to as leaf distortion or stunting.

The overall growth of the plant is stunted, with shortened internodes giving the plant a bushy or compact appearance in severe cases.

Reproductive success is severely compromised, with flower bud abortion and the production of malformed, non-marketable fruit.

• mosaic chlorosis on leaves;
• leaf curling and distortion;
• severe stunting of plants.

The disease is caused by the Jacquemontia mosaic begomovirus, a member of the genus Begomovirus within the Geminiviridae family.

This virus contains a single-stranded DNA genome and relies on insect vectors for transmission between susceptible host plants.

The whitefly Bemisia tabaci serves as the primary vector, acquiring the virus during feeding and transmitting it through its salivary glands.

The virus replicates within the host plant's nuclei, leading to systemic infection and the manifestation of characteristic symptoms across all new foliage.

Once infected, the plant remains a reservoir for the virus, potentially spreading the pathogen to other nearby crops through insect activity.

The spread of the virus is highly dependent on the population density of whiteflies, which increases significantly during warm, dry weather conditions.

High temperatures accelerate the reproductive cycle of the insect vector, leading to rapid increases in the transmission of the virus.

Weedy fields and the proximity of alternate host plants provide a year-round habitat for vectors to sustain the virus in the environment.

Poor agricultural practices, such as failing to remove infected plant debris, contribute to the persistence of the disease in the soil and surroundings.

Lack of proper quarantine measures for nursery stock often leads to the introduction of the virus into previously healthy agricultural plots.

The physiological stress caused by the virus results in significantly lower biomass production and a major reduction in crop yields.

Infected plants show poor photosynthetic efficiency, rendering them less vigorous and more susceptible to environmental stressors.

The market value of the produce is heavily impacted due to cosmetic defects, malformations, and reduced size of the harvested fruits.

Since the virus is systemic and persistent, it often necessitates the complete destruction of infected crops to prevent further spread.

The continuous costs associated with insect control and crop losses represent a substantial economic burden for growers worldwide.

Effective management requires a multi-faceted approach, starting with the intensive control of whitefly populations using appropriate insecticides.

Implementing strict sanitation practices, including the removal of infected plants and weeds, is crucial for reducing the local inoculum source.

The use of certified virus-free planting material is the first line of defense to prevent the initial introduction of the disease.

Crop rotation and the use of physical barriers like insect-proof nets in greenhouses can significantly reduce the risk of transmission.

Choosing resistant or tolerant crop varieties is the most sustainable strategy for long-term management and crop protection.