Plant cabbage with tomato or garlic

By Sosimo Ma. Pablico

CABBAGE FARMERS may as well plant either tomato or garlic around their cabbage crop to reduce damages caused by diamondback moth (DBM), Hellula, cutworms, and other harmful insect pests.

Mrs. Lucrecia Cocson and Mrs. Lagrimas Flojo, researchers of the Mariano Marcos State University [MMSU] in Batac City, Ilocos Norte, found in a three-year study that companion planting with tomato or garlic results in higher marketable yields and, hence, net income of cabbage. The study was conducted in the cool months of October to February from 2004 to 2007.

According to the lady researchers, companion planting is a technique of combining two or more crops with a main crop so that some cultural benefits, usually pest control and higher yields, could be derived. In their study, they observed tomato as the best companion crop of cabbage followed by garlic.

They said that companion planting is one approach in integrated pest management [IPM] that manipulates the environment to take advantage of the insects’ dispersed activities and their preference for one host over another. “This strategy attempts to divert the insects from the main crop by presenting to them a more favorable substitute or a crop that would be deterrent to them,” Cocson and Lagrimas added.

In addition to the reduction of pest problems, companion planting is a very effective way of protecting environmental health and increasing farm productivity.

Results of the study showed that cabbage plus tomato combination significantly reduced the damages caused by Hellula and DBM. On the other hand, the cabbage plus garlic combination reduced cutworm damages.

Hellula is an insect that feeds on cabbage shoots at the early vegetative stage of the plants. Its damages come in either of two ways: one, the crop does not produce any head at all; two, the plants may produce multiple heads that are not marketable.

On the other hand, the DBM larvae are voracious feeders on cabbage heads. This insect may cause farmers to lose 80 to 100 percent of their expected yield if left uncontrolled. Damaged cabbage heads become unmarketable.

Cocson and Flojo harvested a total cabbage head yield of 14.86 tons per hectare in the cabbage + garlic combination, and 13.86 tons per hectare in the cabbage plus tomato combination.

The percentage of marketable yield was higher in the cabbage plus tomato combination (97.7 per cent or 13.54 tons per hectare). In contrast, the cabbage plus garlic combination had only about 85 percent marketable yield (12.58 tons per hectare), resulting in a difference of almost one ton per hectare.

Translated into net income, the cabbage plus tomato combination gave PhP284,560 per hectare, while the cabbage plus garlic combination had only PhP251,190 per hectare.

What is it in tomato and garlic that makes them effective companion crops?

Cocson and Flojo said tomatoes contain a toxin known as tomatin, which makes the plant unpalatable. Tomatin repels the DBM larvae or caterpillars from chewing the cabbage leaves.

On the other hand, garlic contains an active ingredient known as allicin, a sulfur compound produced when the garlic glove and leaves are broken. Allicin deters insects, birds, and worms from feeding on cabbage plants.

Although the two ladies also tested marigold and onion as companion crops, they observed that only tomato and garlic significantly minimized the damage caused by insects.

According to them, farmers who may wish to select other companion crops should observe for the following plant traits:

1. It should have repelling properties like strong aroma and unfavorable taste;

2. Its common pests must not be similar with those of the main crop;

3. It must not compete with the main crop for nutrients and space, and the two must benefit each other;

4. It must be early maturing.

The two ladies recommend that a companion crop should be planted at least three weeks before transplanting cabbage. By then the companion crop has already produced enough leaves and could readily deter insects away from the newly transplanted cabbage.

Plant the companion crop around the cabbage crop û about 0.8 meters along the perimeter and one meter away from the main crop to avoid competition for nutrients and prevent shading.

Cabbage, on the other hand, must be transplanted in sunken beds (at the bottom of he furrows) at a distance of 40 cm x 40 cm. The furrows must be moist to facilitate transplanting. Water the newly transplanted seedlings along the furrows to establish good root contact with the soil.

(Readers may reach columnist at spablico@yahoo.com. For past columns, click http://sundaypunch.prepys.com/archives/category/opinion/harvest-time/ For reactions to this column, click “Send MESSAGES, OPINIONS, COMMENTS” on default page.)

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