Monday , 25 June 2018

Tiny pests: Ash whiteflies

Miguel Braganza

Ash Wednesday is behind us but we will keep encountering the Ash Whitefly wherever we go till the rains come down in June. It is a tiny insect that is gregarious like summer tourists at a beach or devotees at a mela, zatra, fest or gaddye. They shelter themselves from the sun under a mattov or tent of the leaf itself. When disturbed they waft like the specks of ash from a wood fire, hence, the name Ash Whitefly. These whiteflies can bug you to no end and there is a good reason for that—they belong to the family of bugs, Hemiptera. The whiteflies have green leaf hoppers (GLH), brown plant hoppers (BPH), mango hoppers, thrips and cicadas as relatives.

The colourful leaves of the ornamental Acalypha plant are likely to be the Ash Whitefliy’s first target. Guava and citrus fruit trees like limes and lemons come next. Among vegetables, brinjal leaves are their favourite. The insects are tiny, one to three millimetres in size that ten to a dozen of them could sit in a line not more than an inch long. The insect-exclusion nets of the polyhouses cannot keep them out and so those engaged in protected cultivation hang ‘Sticky Fly Traps’ to reduce their population inside. They also use a double-door entrance cubicle to reduce infestation. Whiteflies have an interesting reproduction process that allows for parthenogenesis or birth from a virgin, incest or an offspring mating with its parent. If not checked in the initial stages, Ash Whiteflies can overwhelm the crop with their rapid multiplication.

The best control measure short of using insecticides that I know of is spraying water on the under surface of leaves in case of mild infestation. Pruning twigs and leaves and burning them is the only option in case of major infestation. They have their natural enemies. Pirate Bug and Ladybird Beetle grubs and Lacewing larvae are known to feed on Whitefly eggs and larvae. Some wasps are known to parasitize Whitefly larvae, too.

My friend, Ambrose Vaz, would get for me Anna BB, a Beauvaria bassiana fungal culture, from the seed vendors at Swar Gate, Pune. It is available under the brand name Daman in Goa, now disconnected from Daman & Diu. B R Gawade of Gomantak Agro is the only local dealer as far as I know.

Perhaps, the KVK-North, Karmali; Directorate of Agriculture’s Bio Control Lab, Ela or Don Bosco College of Agriculture, Sulcorna will start producing bio-control agents in Goa to help make the state organic like Bhutan and Sikkim. Goa can even enact a law like Mizoram to prohibit the use of chemicals. We do have a graduate in agriculture in the Goa government now. In a state where people worship the Earth goddess, Sateri and Rawalnath, Goykarponn is also becoming organic and insecticide-free.

The highlight at the Konkan Fruit Fest this year, from April 21 to April 23 in Panaji, will be the biological control of insect pests and fungal diseases in all kinds of crops from fruits to vegetables.

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