Using natural pest enemies, an agricultural natural factor, to protect the ecological environment

Humans need food, and society needs agriculture, so what should we do to develop agriculture better, and is agriculture bound to cause some damage to the ecology? In order to use fewer pesticides and protect the ecology, the "Sharing Nature" special exhibition soon to be held at the Smart Agriculture Pavilion in the Waipu Park of the Taichung World Flora Exposition will showcase Taiwan's "friendly farming" agricultural techniques, so we can see what efforts we can make to reduce the burden on and damage to the environment and move toward a sustainable vision.

The predatory beneficial insect green lacewing is a natural enemy of the pest aphid; controlling pests with insects can naturally achieve ecological balance through the food chain. Mantises, green lacewings, parasitic wasps: an army of natural enemies using insects to control insects. "If the natural enemies in our great outdoors are not killed off, broad-spectrum predators like mantises, as well as green lacewings that deal with small pests, can achieve the effect of controlling pests with insects," said Lu Meijun, director of the Biological Control Branch Station of the Miaoli District Agricultural Research and Extension Station. This "Sharing Nature" exhibition advocates the approach of "taking from nature and giving back to nature."

In nature, there is its own operating principle of balance; there are pests that love to eat vegetables, and there are also beneficial insects that love to eat meat. Predatory beneficial insects such as green lacewings, mantises, and parasitic wasps are precisely the natural enemies of pests, and through the food chain they naturally achieve ecological balance. For example, on farms where a single crop is commonly planted in large quantities, the aphid problem on cruciferous cabbage and bok choy is mostly controlled by spraying pesticides under conventional farming methods. Conversely, in a natural environment with diverse crop types, or for farmers practicing organic or friendly farming, the effect of "controlling pests with insects" can be achieved by rearing the natural enemy green lacewing.

Creating wildflower carpets can increase the number of beneficial insects; the more diverse the species, the more stable the ecosystem will be. Once, in Taiwan's countryside, whether on field ridges, in vegetable gardens, or in wild areas, vibrant native wildflowers could be seen everywhere. Around the 1960s, herbicides began to become widespread, field ridges were gradually paved with concrete, and many native wildflowers and grasses gradually disappeared. In this exhibition, an area with wildflower carpets has been created to let the public understand their importance. For example, planting Asteraceae plants on field ridges, because of the characteristics of Asteraceae of "many flowers and a long flowering period," can increase the number of beneficial insects and suppress common planthopper and moth pests in rice paddies. The more diverse the species, the more stable the ecosystem will be.

Pheromone attractants can be used on the sweet potato weevil, which bores into and ruins sweet potatoes; artificially synthesized sex pheromones can mass-trap adult male weevils. Just like humans, the insect world also has pheromones. Insects release sex pheromones to attract mates. As long as we understand insect habits and make targeted pheromone attractants, we can help farmers strike a balance between ecology and crop harvest. For example, the sweet potato weevil is a culprit that bores sweet potatoes into a mess and causes them to smell foul. Using artificially synthesized sex pheromones can trap large numbers of adult male weevils, making it impossible for female weevils to find mates, so pest damage can be reduced and farmers' harvests protected. "It's not just about love, either. Besides attraction, pheromones also have an alarm function!" Director Lu said with a smile. For example, in a guava field where "alarm pheromones" are placed, thrips, the biggest headache for guava farmers, feel uncomfortable all over as soon as they fly into the field area and fly away.

There are also many environmentally friendly agricultural techniques, such as bee pollination and agroforestry economy, all of which will be presented in the "Sharing Nature" special exhibition at the Smart Agriculture Pavilion in the Waipu Park of the Taichung World Flora Exposition. Let us work together for a sustainable future!