Little leaf of brinjal is caused by mycoplasmas. This phytoplasma disease, transmitted by leafhoppers, leads to stunted growth and small leaves in eggplant plants.

Question Solution

The correct answer is Mycoplasmas. Little leaf disease severely impacts brinjal (eggplant) crops in India, causing economic losses up to 90% if unmanaged.

Option Analysis

• Viruses: Incorrect. Viruses like Tomato Leaf Curl Virus affect brinjal but cause curling and mosaic symptoms, not the characteristic little leaf proliferation.​

• Bacteria: Incorrect. Bacterial wilt (Ralstonia solanacearum) causes wilting and stem rot, distinct from little leaf’s phyllody and witches’ broom.​

• Mycoplasmas: Correct. Specifically, phytoplasma (formerly mycoplasma-like organisms or MLOs) infects phloem, reducing leaf size, inducing chlorosis, virescence, and excessive axillary shoots via vector Hishimonus phycitis.

• Nematodes: Incorrect. Root-knot nematodes (Meloidogyne spp.) cause galls on roots, leading to wilting but not aerial little leaf symptoms.​

Introduction to Brinjal Little Leaf Disease

Little leaf of brinjal, a devastating phytoplasma disease caused by mycoplasmas, threatens eggplant farmers across India. This brinjal little leaf disease reduces yields through tiny leaves, stunted growth, and no fruiting, often leading to 90% crop loss. Early detection and vector control are key to managing this mycoplasma-induced issue.

Causes of Little Leaf in Brinjal

Brinjal little leaf disease is caused by mycoplasmas, now classified as phytoplasma—a wall-less bacterium thriving in plant phloem. Transmitted by the leafhopper Hishimonus phycitis (or Cestius phycitis), it spreads from weeds or alternate hosts like tomato to brinjal. High soil moisture and temperature favor outbreaks.

Symptoms Explained

Infected brinjal plants show light yellow leaves that shrink dramatically, forming a “little leaf” appearance. Additional signs include witches’ broom (excess axillary shoots), phyllody (floral parts turning leafy), chlorosis, and brittle stems with no flowers or fruits. Late infections harden small fruits, making them unmarketable.

Why Not Other Pathogens?

Viruses cause leaf curl but not proliferation; bacteria lead to wilt without little leaves; nematodes attack roots, not foliage. Only mycoplasmas match the full symptom profile of brinjal little leaf disease.

Management Strategies

• Remove and burn infected plants immediately.

• Control vector with insecticides like imidacloprid; apply tetracycline sprays.

• Use resistant brinjal varieties and weed-free fields.

• Seed treatment with benomyl + tetracycline helps prevent spread.