The author is a graduate of Agriculture at the University of the Philippines.A teacher at the Visayas State University, Baybay City, Leyte.
Keywords: Insects. Beneficial. Harmful. Pests Cultural Methods. Pesticides. Natural Control Agents.
“Protect predators of pests, pollinators, our environment, ourselves from the misuse of pesticides. Identify the organism first and then if it is a pest of importance, choose the least toxic way to manage it.”
Quote from Wayne S. Johnson and Jessica Graham (June 2008)
Worldwide distribution of known organisms in each group
Don't be alarmed if you see loopers, flyers and crawlers in your beautiful garden. Those flying objects and crawlers are not all pests. In fact if you look closely, some of those flyers and crawlers are beneficial insects. They help you control the population of harmful insects in your garden by acting as predators, assassins and insect killers.
Insects are the most diverse group of an organism with around 950,000 species described in the animal kingdom. They assume a critical role in both ecology and human society as a vital link to food webs. Served as pollinators and in the recycling of nutrients for increasing productivity of agricultural crops, conversely, insects have devastating consequences as agricultural pests and bears diseases. Insects vary in size and forms but their ability to adapt to extreme temperatures and altitudes makes them superior over other organisms.
The animal kingdom is divided into phyla (sing. phylum), considered the most diverse is Phylum Arthropoda. Under this phylum are six distinct Classes, namely, Class Crustacea, Class Diplodea, Class Arachnida, Class Chilopoda, Class Insecta, and Class Merostomata. However, in terms of numbers and diversity, Class Arachnida and Class Insecta bears the bulk of 950,000 known invertebrates in the Animal Kingdom widely referred to as "insects ", but the arachnids (eg. spiders ) are not insects, they have four pairs of legs while true insects (eg. Honeybees) have three pairs of legs only. Nevertheless, the so-called "insects" are further grouped as beneficial or harmful insects and here's the rub, the harmful insects (pests) out numbers the beneficial insects. But, don't be alarmed, though outnumbered, they're the most effective nature's insecticide.
The common insects in your garden
The first reaction of most gardeners, if they see insects in their gardens, are pests and immediately apply insecticide to get rid of troublesome insects without knowing first the type of insects present. Spraying of insecticide also kills beneficial insects and this my led to resurgence of harmful insects as the population of natural control agents is lowered Furthermore, the use of chemical as control agents may threaten human health as residues are left on the food crops and could potentially contaminate our water resources if applied enlarged amount.
Knowing what are the insects present in your garden before any control measures done, is basic to the effective reduction of harmful insects in your garden. Some of these common insects found in your garden is shown below.
Do you Know ?
Can aphids have offspring without mating?
That Assassin bug inject toxic saliva that paralyzes and liquefies victim's tissue before feeding?
That ladybird beetle's larvae feed for three weeks, eating 10 to 50 aphids per day?
That honeybees communicate with each other using the " dance " language?
That ants have two stomachs, one to digest its own food, the other to feed other ants?
That the larvae of periodic cicada live about 13 to 17 years below ground, but as an adult two weeks to 40 days only?
One maggot of Syrphid fly can consume 400 to 500 aphids in its lifetime? They have 3 to 7 generations per year.
What are beneficial and harmful insects
Insects are important components to our world as they are sources of food to other animals including man, they aid in the pollination or reproduction of food crops and they have inspired humans with their beauty and ingenuity, and even worshiped in ancient religion. Therefore, don't be alarmed if yo see insects in your garden, not all insects are harmful, in fact, some of them help toned down pest population Shown below is some common insects usually observed in your garden, they are classified as beneficial or harmful insects, try to familiarize with them and understand how they affect your crops. If you can secure an illustrated guide to common insects in your area will be most advantageous. A list of examples is shown below.
Examples of Beneficial and Harmful insects in your garden
|Beneficial Insects||Harmful Insects|
green lace wings
lady bird beetles
bean leaf beetls
minute pirate bugs
squash vine borers
predatory stink bugs
european corn borers
tomato & tobacco hornworms
What are garden pests :
These are garden insects that destroy your plants. As insect pests, they destroy roots, bore tunnels in the stem, stunt growth, blemishes flowers and leaves, deformed fruits and above all make yours product unpalatable and unfit for market. The damage done by garden pests can be arbitrarily categorized as a) the fruit and flower destroyer, b) the leaf and root cutters, c) the stem borers and gall makers, d) the flower and flower buds destroyer, and e)seedling feeding pests. The list of insects in each category is not absolute, in fact, some of these garden pests are present all year round especially those having multiple plant hosts. therefore, eradicating them will be difficult. In this case, a robust control measure should be planned prior to planting.
a) The fruit blemishers and flower destroyer
The following insects are considered pests that damaged flowers and fruits such as:
Borers, Mealybugs, worms
petal cutters, Mites
Beetles, Japanese, Scales
Aphids, and Thrips
Bug, Squash and Whiteflies
b) The leaf and root cutters
The following insects are considered pests such as:
The foliage eaters, Sawfly
Armyworms, Tomato hornworm
Corn earworms, Grasshoppers
Midges.Aphids, and Cicadas
c) The stem suckers and gall makers
The following insects are considered pests in stems of such as:
Aphids, Bugs, Squash
Mites, Scales, Beetles, Japanese
Thrips and Whiteflies
d) The flower and flower buds destroyer
The following insects are pests to flowers and flower buds such as:
Weevils, Corn borers
Grasshoppers, Corn Earworms
and Tomato Hornworms
e)The root feeding pests
The following insects are considered pests to roots such as:
Root feeding insects,
White grubs, and Cicadas
Do you know ?
BUTTERFLY vs MOTH
- thin antennas ⁄ feathery
- wings closed at rest ⁄ wings often at rest
- pupa-chrysalis ⁄ cocoon
- diurnal-active day ⁄ nocturnal-active night
Methods how to attract beneficial insects in your garden
|Beneficial Insects||Methods to Attract|
grow pollen bearing and nectar producing plants; provide water in shallow pans filled with gravel duringt dry months
Hover flies or Syrphid flies
grow pollen bearing and pollen producing plants in the Umbelliferae family. Allow some brocolli to flower.Plant tall plaqnts like sunflowers where fleis can hover.
grow perennials to provide permanent shelter plantings
Grow plants in Umbelliferae family and other small-flowered plants like Alyssum and spermint
grow pollen and nectar plants inthe Umbelliferae family, mints and herbs.Legumenous cover crops planted adjuscent to garden beds , ptovide shelter like sunflower, let some Brocoli and radishes flower
grow pollen producing plants, grow dense cover cropsto provde sherter, incorporate stone walkways between garden beds
Big-eyed bugs/flower bugs
grow pollen and nectar plants like sweet alyssum, alfalfa, golden rod and cosmos
Predators, assassins, killers and prey
These are your garden allies that will help you in controlling harmful insects the natural way. Considered as nature's own pesticide is more economical and environmentally friendly. Though their numbers are limited but they helped toned down pest population in a mutualistic way. Plants and insects have co-evolved over 300 million years ago when flowering plants(The Angiosperms) start to dominate the plant world. They are the first inhabitants of this world. Under the mutualistic condition, plants and insects co-exist, whatever damage imposed by insects to plants, plants was able to outgrow the damage. For instance, insects are not destructive to plants at all times only a certain part of their life cycle they do damage to plants example their larval stage. In the adult stage many insects help plants by serving as pollinators or promoting sexual reproduction, the plants get pollinated as requisite for species survival for generations to come, in return the insects gets its food(honey, nectar, etc,), a place to live among others.This mutualistic understanding have persisted for millions of years and has been encoded in their genome to be expressed in their behavioral response to each other.Indeed, plants, predators, assassin's. killer insects and prey are one in the insect food web. Man does not take this relationship seriously in his desire to produce more food for his own kind. Methods used by man altered this relationship (eg. use of pesticides) which created more problems rather than solving it. Some suggestion to keep beneficial insects in your garden ( selected techniques) is presented here(Table).
Pollen bearing and Nectar producing plants
Queen's Ann Lace
Source: Heidi Minga
Do you know ?
- that red ants are not true ants but a kind of wasp?It is also known as "cow killer" it can sting humans and animals
- that damselfly fly at the speed of 30 kph?
- Have that cockroaches their skeleton outside their bodies?
- that butterfly taste using their feet?
- that grasshoppers have five eyes but no ears?instead, they have a special organ called tympana
Matching type. Match column A with B. Letters ONLY.
column A column B
- ---Have 3 pairs of legs a.Metamorphosis
- ---Have 4 pairs of legs b.Honeybees
- ---Scutellum c.Bugs
- ---Change in forms d.Insects
- ---“Dance” language e.Spiders
Methods used in increasing population of beneficial insects in your garden
Plant resistant varierties of crops
How to increase the population of beneficial insects in your gardin
Don't kill insects unless you know them first, chemical control will be the last resort. There are natural methods that are inexpensive and less dangerous to human health. Some of these methods employed by wise gardeners may include cultural. biological or physical. Of course, the technique(s) to use is site or situation specific and depends on the knowledge and experience of the grower. Nevertheless, some these methods are presented, the table below enumerates some of these methods.
Cultural methods and management practices
Cultural methods and management practices are very vital to the life of insects whether beneficial or harmful may vary from location to location.Nevertheless, the main reason for doing this is to increase the presence of beneficial insects in your garden.To a wise grower means fewer costs and less harmful to humans. In the last few years, interest on organic farming has increased due to the ecological impact of pesticides to human health. Some cultural methods are discussed here to minimized dependence to a pesticide to control insect pests in your garden. Crop rotation, this means you don't plant same crop every cropping season to prevent build up of insect pest population in your garden, mono-cropping tend to attract more specialist insect pests to your crop and low population of beneficial insects due less varied food sources.Companion crops. these are crops design to attract the insect to stay in your garden though they are not the main crop, but they provide varied food sources to beneficial insects. Planting them few rows with main crop especially if they are pollen bearing or nectar producing plants will encourage beneficial insects to take up residence in your garden. Some plant gives off compound that repel harmful insects, for example, planting garlic among vegetables help repel Japanese beetles, Aphids, vegetable weevils and spider mites.Trap plants. Some insects prefer one plant over the other.For example, pickle worms prefer squash to cucumber, some tomato worms prefer dill over tomatoes, planting them near your plant will lure away insect pests from the plants you wish to protect. Healthy soil. With healthy soil, you're giving the plants better-growing condition, thus, making them tolerant to pest damages. Humic acid in the soil repel some soil insect pest, increase humic acid can be enhanced by incorporating organic matter in the soil. The more organic matter increase water-holding capacity of the soil increase aggregation for better root penetration, increase nutrient availability among others. Use plant materials only animal materials may attract rodents and other animals aside from the unhealthy odor it emits.
Rotate crops in different families
peas and beans
cabbge, collards, brocoli, brussels sprout,
kale, caulifower, turnips and radish
carrots, parsley, celery,parsnip
tomato, potato, peper and egg plant
lettuce, endive, ariichoke
onion, garlic, shalot, asparagus
Diversified planting. a common practice among home growers to plant a single crop in a straight row wich provide easy movement of pests in and around the rows of plants, therefore, pests damage is increased.Diversified planting means planting different crops in alternate rows that tend to disorient harmful insects where the food is. Transferring from one plant to another exposes them to predators.Compost. Fertile soil is the foundation of a healthy garden. One of the most effective ways to enhance soil fertility is to add compost. Compost is made by mixing organic materials especially plant sources and allowing to decay the natural process. Mulch. Mulching is the spreading of organic matter in the garden and around the plants, It is an effective method to control weeds and also serves as a refuge for predatory insects like the ground beetles. It conserves moisture and lower soil temperature. Some gardeners used cover crops as green mulch. Resistant varieties. Planting resistant varieties gives you an insurance against pest attack. Of course, it does not mean that your plant will not attack by insect pests but, if ever, plants outgrow the damage. Biological. The use of parasitic insects as biological control agents in recent years has gained interest in pest control. There are two distinct groups based on the manner how they obtained food. Parasites, invade the body of their host (endoparasites), or attach themselves to the host (ectoparasites) and feed on it while it is still living. An example of endoparasite, Tachinid flies (Tachinidae) while some wasp's larvae are ectoparasites. Barriers, traps, and stakes. These physical methods are quite limited in application since it can be applied only to few plants especially the exotic ones.
Recommendations and conclusion
To keep your garden healthy and free of harmful insects the following are recommended: don't kill insects unless you know them. If it can't be avoided, the use of pesticides will be the last resort, obtain an illustrated guide to common insects in your locality for quick reference, consult extension agents assigned to your area for appropriate control measures, provide adequate habitat and food supply for beneficial insects to stay in your garden , plant variety of plants that will provide nectar and pollen for beneficial insects throughout the growing season , provide fresh water in shallow pans for them to drink, using hay or straw as mulch around your vegetables for habitat of ground dwelling beneficial insects. Other cultural management practices appropriate for your garden can be employed in combination with other methods to control pest the natural way.
Lastly, the use of pesticides must be avoided beneficial insects are also harmed and pose a greater threat to human health and the environment.
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