A trap crop is a plant that attracts agricultural pests, usually insects, away from nearby target crops. This form of companion planting can save a target crop from decimation by pests without the use of artificial pesticides. A trap crop is used for attracting the insect and pests away from a target crop field. Many trap crops have successfully diverted pests from focal crops in small scale greenhouse, garden and field experiments; [1] a small portion of these plants have been shown to reduce pest damage at larger commercial scales. [1] [2] A common explanation for reported trap cropping failures, is that attractive trap plants only protect nearby plants if the insects do not move back into the target crop. In a review of 100 trap cropping examples in 2006, only 10 trap crops were classified as successful at a commercial scale, [2] and in all successful cases, trap cropping was supplemented with management practices that specifically limited insect dispersal from the trap crop back into the target crop. [2]
Examples of trap crops include:
Trap crops can be planted around the circumference of the field to be protected, which is assumed to act as a barrier for entry by pests, or they can be interspersed among the main crop, for example being planted every ninth row. Planting crops in rows helps facilitate supplemental management practices that prevent insect pest dispersal back into the main field, [2] such as driving a vehicle above the trap crop which then removes insect pests by vacuuming them off of the trap crop row [7] or targeted insecticides, which are only deployed on the trap crop. [8] Even if pesticides are used to control insects on the trap crop, total pesticides are greatly reduced in this scenario over conventional agricultural pesticide applications because they are only deployed on a small portion of the farm (the trap crop). [2] Other strategies that prevent dispersal of insect pests back into the main crop include cutting the trap plants, [9] applying predators or parasitoids to the trap plant that eat the pest, [10] and planting a high ratio of trap plants to other plants. [2]
Trap crops, when used on an industrial scale, are generally planted at a key time in the pest's life-cycle, and then destroyed before that life-cycle finishes and the pest might have transferred from the trap plants to the main crop. [11]
Recent studies on host-plant finding have shown that flying pests are far less successful if their host-plants are surrounded by any other plant, or even "decoy-plants" made of green plastic, cardboard or any other green material. [12] The host-plant finding process occurs in three phases.
The first phase is stimulation by odours characteristic to the host-plant. This induces the insect to try to land on the plant it seeks. But insects avoid landing on brown (bare) soil. So if only the host-plant is present, the insects will quasi-systematically find it by landing on the only green thing around. This is called an "appropriate landing". When it does an "inappropriate landing", it flies off to any other nearby patch of green. It eventually leaves the area if there are too many "inappropriate" landings.
The second phase of host-plant finding is for the insect to make short flights from leaf to leaf to assess the plant's overall suitability. The number of leaf-to-leaf flights varies according to the insect species and to the host-plant stimulus received from each leaf. But the insect must accumulate sufficient stimuli from the host-plant to lay eggs; so it must make a certain number of consecutive "appropriate" landings. Hence if it makes an "inappropriate landing", the assessment of that plant is negative and the insect must start the process anew. [12]
Thus, a clover ground cover was shown to have the same disruptive effect on eight pest species from four insect orders. An experiment showed that 36% of cabbage root flies laid eggs beside cabbages growing in bare soil (which resulted in no crop), compared with only 7% beside cabbages growing in clover (which allowed a good crop). Moreover, simple decoys made of green cardboard disrupted appropriate landings just as well as the clover. [12]
Companion planting in gardening and agriculture is the planting of different crops in proximity for any of a number of different reasons, including weed suppression, pest control, pollination, providing habitat for beneficial insects, maximizing use of space, and to otherwise increase crop productivity. Companion planting is a form of polyculture.
The Japanese beetle is a species of scarab beetle. Due to the presence of natural predators, the Japanese beetle is not considered a pest in its native Japan, but in North America and some regions of Europe, it is a noted pest to roughly 300 species of plants. Some of these plants include rose bushes, grapes, hops, canna, crape myrtles, birch trees, linden trees, and others.
Whiteflies are Hemipterans that typically feed on the undersides of plant leaves. They comprise the family Aleyrodidae, the only family in the superfamily Aleyrodoidea. More than 1550 species have been described.
Leptoglossus phyllopus or eastern leaf-footed bug is a species of leaf-footed bugs in the same genus as the western conifer seed bug (L. occidentalis. The Eastern leaf-footed bug is found throughout the southern United States, from Florida to California, through Mexico, and as far south as Costa Rica.
Anasa tristis is a species of bug in the family Coreidae. It is a major pest of squash and pumpkins, found throughout North America, and is a vector of the cucurbit yellow vine disease bacterium. These bugs can emit an unpleasant odor when disturbed. It is commonly known as the squash bug but shares this name with certain other species.
The silverleaf whitefly is one of several species of whitefly that are currently important agricultural pests. A review in 2011 concluded that the silverleaf whitefly is actually a species complex containing at least 40 morphologically indistinguishable species.
The Miridae are a large and diverse insect family at one time known by the taxonomic synonym Capsidae. Species in the family may be referred to as capsid bugs or "mirid bugs". Common names include plant bugs, leaf bugs, and grass bugs. It is the largest family of true bugs belonging to the suborder Heteroptera; it includes over 10,000 known species, and new ones are being described constantly. Most widely known mirids are species that are notorious agricultural pests that pierce plant tissues, feed on the sap, and sometimes transmit viral plant diseases. Some species however, are predatory.
The genus Lygus includes over 40 species of plant-feeding insects in the family Miridae. The term lygus bug is used for any member of genus Lygus.
The tarnished plant bug (TPB), Lygus lineolaris, is a species of plant-feeding insect in the family Miridae. It has piercing-sucking mouthparts and has become a serious pest on small fruits and vegetables in North America. It is considered a highly polyphagous species and feeds on over half of all commercially grown crop plants, but favors cotton, alfalfa, beans, stone fruits, and conifer seedlings. A study done in southwestern Quebec, Canada has investigated the presence of L. lineolaris in a commercial vineyard. This study also indicated that weeds that grow from cultivation of crops serve as an important food source for L. lineolaris. This insect can be found across North America, from northern Canada to southern Mexico. Adults grow up to 6.5 mm in length, and are brown with accents of yellow, orange or red, with a light-colored "V" on the back (dorsal). The genome has recently been sequenced for the first time.
The diamondback moth, sometimes called the cabbage moth, is a moth species of the family Plutellidae and genus Plutella. The small, grayish-brown moth sometimes has a cream-colored band that forms a diamond along its back. The species may have originated in Europe, South Africa, or the Mediterranean region, but it has now spread worldwide.
The harlequin cabbage bug, also known as calico bug, fire bug or harlequin bug, is a black stinkbug of the family Pentatomidae, brilliantly marked with red, orange, yellow and white markings. It is a major pest of cabbage and related crops in the Brassicaceae, as well as the ornamental flower cleome throughout tropical and North America, especially the warmer parts of the United States. Nymphs are active during the summer and in the tropics the bug can achieve three to six generations a year. In the northern range there is only one generation annually and the insects overwinter as adults in crop residues or field edges. Organic control involves hand-picking the insects off the plants and being especially careful to remove and destroy all the eggs, which are black-and-white striped, laid in clutches of twelve.
Adelphocoris lineolatus, is commonly known as the Lucerne bug or the alfalfa plant bug, and belongs to the family Miridae. It is an agricultural pest causing vast amounts of damage to numerous crops, but primarily to alfalfa crops around the globe.
Crocidolomia pavonana is a moth of the family Crambidae. Its caterpillar is a crop pest and is known as the croci or the cabbage cluster caterpillar. This moth is found in Africa and Asia, its range extending from South Africa through India to the Pacific Ocean, including Australia. The wingspan is about 25 mm (1 in). The larvae feed on Brassicaceae species and are considered an agricultural pest on cabbages. The species was first described by Johan Christian Fabricius in 1794.
Peristenus pseudopallipes is a parasitoid, which lives within a host as part of its life cycle. It then emerges from the host organism, killing the host.
Rhopalosiphum rufiabdominale, the rice root aphid or red rice root aphid, is a sap-sucking insect pest with a wide host range and a global distribution. As a member of the superfamily Aphidoidea, it is one of 16 species of the genus Rhopalosiphum. Adults and nymphs are soft-bodied and usually dark green with brown, red, or yellow tones. Like all aphids, reproduction is sexual and asexual, depending on the environmental conditions and host plant. Rice root aphids cause injury to external plant parts, namely the roots or stem, by feeding on plant sap and vector several important plant viruses. The hosts of this pest extend across multiple plant families with most belonging to Rosaceae, Poaceae, and Solanaceae. R. rufiabdominale is universally associated with Prunus species but also infests various field crops, greenhouse vegetables, cannabis, and other ornamental plants. While this aphid originates from east Asia, it spans nearly every continent. Dispersal is particularly widespread across the United States, India, and Australia, with crop damage documented in multiple instances, although economic losses are primarily associated with Japanese rice crops. Nonetheless, it remains a pest of serious concern due to its high mobility, discrete habitat, and adaptive plasticity, giving it the rightful reputation as a successful invader.
Potato leafhopper belongs to family Cicadellidae and genus Empoasca within order Hemiptera. In North America they are a serious agricultural pest. Every year millions of dollars are lost from reduced crop yields and on pest management. Crops that are impacted the most are potatoes, clover, beans, apples and alfalfa.
Lygus gemellatus is a species of plant-feeding insects in the family Miridae.
Lygus rugulipennis, the European tarnished plant bug, is a species of plant bugs of the family Miridae.
Creontiades dilutus, commonly known as the green mirid, is a member of the bug family Miridae. This insect is considered a "generalist" feeding on over 100 plant species, and is also a major economic pest on several important agricultural crops.
Lygus punctatus is a species of plant bug in the family Miridae.