What a pest (Part II)

Powdery mildews and mealy bugs are the biggest problems faced by gardeners. Here are some non-chemical, DIY solutions to keep them away.

In the previous article we discussed about handling pests in general. Here are a few examples shared to show how pests can perhaps be dealt with, without the use of chemicals and dangerous pesticides.

Powdery Mildew

Caused by fungi, the leaves in this case develop cloudy whitish spots are a common problem faced by several terrace gardeners. Starting out as a few spores on the leaves, powdery mildew quickly spreads, ultimately yellowing the leaves and causing leaf drop. It stunts plant growth, distorts the flowers and fruits and weakens the plant in general. Spores never stop producing more spores, so if infected leaves are not destroyed, the problem will only worsen. Infected plants parts need to be destroyed and cannot be composted.

Mealybug. Pic: Vinita G

Some experts suggest that a spray made with baking soda, if applied weekly at the first signs of infection, can protect plants against further damage. Dr Viswanath also suggests using turmeric powder in combination with wood ash. One of the most effective measures believed to prevent and treat powdery mildew is to spray the leaves of plants daily with plain water from the hose. Powdery mildew hates water! However this must be done early morning so that the leaves dry by evening; otherwise it would serve as an optimum situation for other fungal diseases, such as black spot, in the garden.


In the early days of my garden, I have been harassed a fair deal by the Mealybug! Of course I now realise that it was probably because I had not ensured that the soil was healthy enough.

Mealybugs tend to gather on the affected plant in large numbers, forming white cottony masses. They start at the newer growth tips and spread to ‘hard to reach’ areas like the underside of leaves, inside fruit bunches, crevices of the bark and stem. They cause damage by sucking the juice from the host plant and secreting a waxy susbtance that sometimes even causes other fungal growth like black sooty mold.

Like most pests, the best control for mealy bugs is defensive. Healthy, vigorous plants are less susceptible to infestation than weak and stressed plants. Mealy bugs can be dislodged with a steady stream of water. Repeat the treatment as necessary. This works well for light infestations. Neem oil acts as a fungicide and plants can absorb it so that they develop a greater resistance.

If an infestation cannot be controlled after two or three weekly applications of insecticide, consider destroying the plant before the mealybugs spread to other plants in your home.

DIY ‘solutions’

  • It is believed that sprinkling baking soda lightly on the soil around tomato plants sweetens tomatoes by lowering their acidity and discourages pests.
  • Another suggested organic solution includes 1 teaspoon baking soda in 1/3 cup cooking oil. From this mixture, measure 2 teaspoons to combine with 1 cup water and fill plant sprayer. This spray is said to work for aphids, spider mites and white flies, and to be benign to beneficial insects.
  • All purpose garden spray that uses a mixture of 50g each of chilli, ginger, garlic onion and pepper (any 3). This is ground in the mixie and mixed with 150ml water. Then another 350ml water is added and the solution filtered. Further dilute to 1 litre and used as a spray on plants.
  • Interspersing marigold plants is one of the best forms biological control in an organic garden (more in a future post on companion planting). A marigold spray is made from 1 cup of mashed marigold leaves and flowers soaked for a day in 500ml of water and strained. Dilute this with another 1.5 litre of water and add 5ml of liquid soap (like soapnut solution). Use this as a spray on affected plant areas to organically repel chewing and leaf cutting insects.
  • For fungal diseases like mildews, leaf spots, stem and root rots, use sweet flag extract 5% spray. (Make sweet flag/baje rhizomes to powder, soak 50g of it overnight, take the filtrate and make the volume to 1 liter and spray well on the plants. Repeat after 10 days especially during humid seasons and later if required).
  • A similar spray made up of 5% of Shikakai can be used against mealybugs.
  • For aphids and mites a 5% spray of Chilli, Garlic, Ginger (50g together) would work well. To ensure that it is effective, the spray is best repeated after every 10-15 days.
  • Neem seed extract for mealy bugs, aphids, thrips, beetle and caterpillar pests.

A rule of thumb is to first test any new spray on a leaf before applying it on the whole plant; to ensure it does not cause any further damage to the plant.

In cases where you feel you are up against something entirely new – a strange looking ‘insect’ or an unfamiliar presence on the plant, a good place to address your queries is on the Bangalore Terrace Gardeners group on Facebook or here. More often than not, there will be someone who has faced a similar situation, someone who can suggest what to do or someone who helps you view the situation in a better light.

For instance one of the members found out that the yellow spots on her curry leaf plants are actually eggs of butterfly! And that the curry leaf plant could indeed sustain these eggs without any problems.

Perhaps we would do well to remind ourselves time and again that, without insects there would be no humans on the Earth; so its time we found a way of respecting their existence and working our gardens around it.


  1. Hemavathi A. Balikai says:

    I have a small kitchen garden on the terrace of my house and I grow quite a few variety of vegetables and flowers organically.However of late monkeys have started attacking the vegetables especially the french beans, brinjals and capsicums. How do I get rid of this menace?

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