In conventional farming, a commonly used practice to kill pests is inorganic pesticides. It may help the plant grow, but is it truly beneficial, especially if it will compromise the health of the farmers and consumers in the long run?
Fortunately, there are alternative methods to combat pests such as good agricultural practices (GAP), and organic agriculture using organic inputs, cultural and biological control, crop rotation, and composting, among others.
Agent of farms
Aside from the aforementioned, the use of biological control agents (BCAs) is also being encouraged by the Department of Agriculture (DA) to eradicate crop pests. BCAs are composed of parasitoids, predators, and pathogens/entomogenous microorganisms that naturally control populations of other organisms.
The BCAs are being produced, and reared by the DA – Cordillera (DA-CAR) through the Regional Crop Protection Center (RCPC), as they are outnumbered by the pests in farm fields.
Green lacewings (Chrysoperla sp.) are common insects found all over North America and belong to the Chrysopidae family, which includes about 1,200 species of predatory insects. The larvae of these species are voracious feeders and devour various crop pests, including aphids, scale insects, caterpillars, thrips, mealybugs, whiteflies, spider mites, psyllids, insect eggs, and other soft-bodied insects.
The green lacewing adults are flying insects that feed on nectar, pollen, and honeydew (a sugar-rich liquid secreted by insects that feed on plant sap). They are widely used in augmentation biological control to suppress pests. Mature lacewings are most active in summer.
The Culprit
Aphids are one of the farmers’ many enemies. Aphids inflict direct and indirect damage on a wide variety of host plants. Direct damage includes the removal of valuable nutrients and water from the plant by piercing, causing leaves to curl, wilt, and turn yellow. Severe infestations can lead to stunted growth and reduced plant vigor. Conversely, indirect damage is the transmission of plant viruses and the excretion of honeydew as they feed, which can attract ants and also promote the growth of fungus (sooty mold) on plant surfaces.
Additionally, these viruses can cause a range of symptoms, including leaf distortion, mosaic patterns, and necrosis, ultimately impacting plant health and reducing yields. During the average lifespan of one month, aphids can produce 40-85 offspring, depending on the species. Some aphids have wings, while others do not.
Lacewing vs. aphids
Lacewing larvae feed on 50 aphids per day. Using its mandible (mouthpart), the larvae will suck the aphids until they become dry. The lacewing will then collect the aphids’ carcass to its back and this will serve as the larvae’s protective layer until it becomes pupae. According to Chona Sakiwat, Agriculturist I from the RCPC, caring and monitoring for green lacewing is essential as they are also prey to its kind, which reduces their population. When released in the field, they are vulnerable to predators including ants.
A how-to guide
To significantly reduce the culprit in your crops, release lacewings early in the season or as soon as pests are present. Release them early in the morning or late in the afternoon, as temperatures above 30 °C are not suitable for lacewing release. This also increases their chances of survival because they are less likely to be preyed upon by other insects that are more active later in the day.
Evenly shake the container overall plants in the crop or by simply opening and hanging the brown paper bag to the stems or branches of the crop, concentrating on the pests’ hot spot. Release 25 pieces of green lacewing per square meter of vegetables and fruit trees as the initial population. After the first release, follow up with two further augmentations, 10-14 days apart, depending on the pest’s population. By Cy-j E. Waytan
