Nip the evil in the bud

Satish Narula

Winter is the time when most of the insects too go underground to escape cold. However, there are still many who work under the protection of a cover. And that gives them immunity from the insecticides normally used to control the other types. Let us get

introduced and find out the ways to control them. Important for this time of the year are red rose scale and leaf miner. The most dreaded aspect of these insects is that they are not moving or visible movers and thus go undetected. Where as the red rose scale

is mostly confined to roses, the miner is polyphagus and could be seen on citrus species plants like kinnow, lemon, grapefruit, ornamental like nasturtium, cineraria, dahlia and the vegetables like sarson, peas, tomato etc.

Let us deal with these one by one.

The red rose scale appears on the stem of the plant as reddish small pox like postules that are irregular in shape. Scrap it with nail and these are removed to show a green stem below. In fact the insect

becomes stationary at a point on the main stem and then keeps sucking sap from it. It creates a covering on its body to escape detection and predators. The covering also gives them immunity against chemicals

most of which are either stomach (act when ingested) or contact insecticides. We will deal with the control measure once we are through with the other type too.

Leaf miner is also dreaded by the gardeners as it distorts leaf that also loses vitality. There appear zig-zag lines on the surface of the leaf or on the back of it. The minute larva creates a parchment like covering on the leaf under which it keeps moving slowly sucking sap. Since the pattern made by them is like underground mines, they derive their name from that. In this case too, the stomach and contact insecticides fail to act. When the roses are being grown on home scale then one could go in for

rub and clean method of controlling red scales. For this, use an old tooth brush and dip it in either of these chemicals; ekalux, rogor or

metasystox to rub clean the stems. In the larger gardens one could apply thimet 10-G granules, at ten grams per bush repeating the application at least thrice. Rogor and metasystox being systemic in

nature (go into the system of plant) are used to control insects like leaf miner that have natural immunity against direct touch. The insects die within their mine when ingest the sprayed plant sap.

Thimet 10-G can also be used against this insect but its uses should be restricted only to the ornamentals and not in case of vegetables or the near ripening fruits. Do not handle the granules with bare hands.

(Narula is a senior horticulturist and landscapist)