Biological Control Of The Chain-Fruit Cholla: Part 2

The cochineal insect is a highly effective biocontrol method for dealing with this invasive cactus; it can kill a large cactus in a relatively short time.

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As discussed in the previous issue, the invasive cactus species, Cylindropuntia fulgida, can be controlled effectively with a tiny, sap-sucking insect, the cochineal (Dactylopius tomentosus).

To ensure effective control, the cochineals should be distributed manually on pieces of their host plant, to other cacti. Without this intervention, they will disperse only as far as the wind takes them (about 5m).

HARVESTING AND RELEASING COCHINEALS

Look for white woolly fluff on the spines of a stem segment (cladode). Harvest the cochineals by breaking infested cladodes off the mother plant with a pair of tongs. Grip each cladode in turn and twist it off without damaging it unnecessarily. If badly damaged, it may dry out or rot, and the female cochineals will die before they complete their life cycle.

Harvest enough infested cladodes to distribute within a week of collection.

Place the harvested cladodes in a collection container and cover with a lid to prevent the crawlers and mature males from escaping.