Lettuce is an annual plant of the daisy family, Asteraceae. It is most often grown as a leaf vegetable, but sometimes for its stem and seeds. Lettuce is most often used for salads, although it is also seen in other kinds of food, such as soups, sandwiches and wraps; it can also be grilled. One variety, the celtuce, is grown for its stems, which are eaten either raw or cooked. In addition to its main use as a leafy green, it has also gathered religious and medicinal significance over centuries of human consumption. Europe and North America originally dominated the market for lettuce, but by the late 20th century the consumption of lettuce had spread throughout the world. As of 2017, world production of lettuce and chicory was 27 million tonnes, 56% of which came from China.
Aphids are small sap-sucking insects and members of the superfamily Aphidoidea. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The group includes the fluffy white woolly aphids. A typical life cycle involves flightless females giving live birth to female nymphs—who may also be already pregnant, an adaptation scientists call telescopic development—without the involvement of males. Maturing rapidly, females breed profusely so that the number of these insects multiplies quickly. Winged females may develop later in the season, allowing the insects to colonize new plants. In temperate regions, a phase of sexual reproduction occurs in the autumn, with the insects often overwintering as eggs.
Hemiptera is an order of insects, commonly called true bugs, comprising over 80,000 species within groups such as the cicadas, aphids, planthoppers, leafhoppers, bed bugs, and shield bugs. They range in size from 1 mm (0.04 in) to around 15 cm (6 in), and share a common arrangement of sucking mouthparts. The name "true bugs" is often limited to the suborder Heteroptera.
Galls or cecidia are a kind of swelling growth on the external tissues of plants, fungi, or animals. Plant galls are abnormal outgrowths of plant tissues, similar to benign tumors or warts in animals. They can be caused by various parasites, from viruses, fungi and bacteria, to other plants, insects and mites. Plant galls are often highly organized structures so that the cause of the gall can often be determined without the actual agent being identified. This applies particularly to some insect and mite plant galls. The study of plant galls is known as cecidology.
The Russian wheat aphid is an aphid that can cause significant losses in cereal crops. The species was introduced to the United States in 1986 and is considered an invasive species there. This aphid is pale green and up to 2 mm long. Cornicles are very short, rounded, and appear to be lacking. There is an appendage above the cauda giving the aphid the appearance of having two tails. The saliva of this aphid is toxic to the plant and causes whitish striping on cereal leaves. Feeding by this aphid will also cause the flag leaf to turn white and curl around the head causing incomplete head emergence. Its host plants are cereal grain crops including wheat and barley and to a lesser extent, wild grasses such as wheatgrasses, brome-grasses, ryegrasses and anything in the grass family.
Lactuca serriola, also called prickly lettuce, milk thistle, compass plant, and scarole, is an annual or biennial plant in the dandelion tribe within the daisy family. It has a slightly fetid odor and is commonly considered a weed of orchards, roadsides and field crops. It is the closest wild relative of cultivated lettuce.
Parasitoid wasps are a large group of hymenopteran superfamilies, with all but the wood wasps (Orussoidea) being in the wasp-waisted Apocrita. As parasitoids, they lay their eggs on or in the bodies of other arthropods, sooner or later causing the death of these hosts. Different species specialise in hosts from different insect orders, most often Lepidoptera, though some select beetles, flies, or bugs; the spider wasps (Pompilidae) exclusively attack spiders.
Lactuca muralis, the wall lettuce, is a perennial flowering plant in the dandelion tribe within the daisy family, also referred to as Mycelis muralis (L.) Dumort.
A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder. The wasps do not constitute a clade, a complete natural group with a single ancestor, as bees and ants are deeply nested within the wasps, having evolved from wasp ancestors. Wasps that are members of the clade Aculeata can sting their prey.
The soybean aphid is an insect pest of soybean that is exotic to North America. The soybean aphid is native to Asia. It has been described as a common pest of soybeans in China and as an occasional pest of soybeans in Indonesia, Japan, Korea, Malaysia, the Philippines, and Thailand. The soybean aphid was first documented in North America in Wisconsin in July 2000. Ragsdale et al. (2004) noted that the soybean aphid probably arrived in North America earlier than 2000, but remained undetected for a period of time. Venette and Ragsdale (2004) suggested that Japan probably served as the point of origin for the soybean aphid's North American invasion. By 2003, the soybean aphid had been documented in Delaware, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Michigan, Minnesota, Mississippi, Missouri, Nebraska, New York, North Dakota, Ohio, Pennsylvania, South Dakota, Virginia, West Virginia, and Wisconsin. Together, these states accounted for 89% of the 63,600,000 acres (257,000 km2) of soybean planted in the United States in 2007.
Myzus persicae, known as the green peach aphid, greenfly, or the peach-potato aphid, is a small green aphid belonging to the order Hemiptera. It is the most significant aphid pest of peach trees, causing decreased growth, shrivelling of the leaves and the death of various tissues. It also acts as a vector for the transport of plant viruses such as cucumber mosaic virus (CMV), potato virus Y (PVY) and tobacco etch virus (TEV). Potato virus Y and potato leafroll virus can be passed to members of the nightshade/potato family (Solanaceae), and various mosaic viruses to many other food crops.
Acyrthosiphon pisum, commonly known as the pea aphid, is a sap-sucking insect in the family Aphididae. It feeds on several species of legumes worldwide, including forage crops, such as pea, clover, alfalfa, and broad bean, and ranks among the aphid species of major agronomical importance. The pea aphid is a model organism for biological study whose genome has been sequenced and annotated.
Phylloxeridae is a small family of plant-parasitic hemipterans closely related to aphids with only 75 described species. This group comprises two subfamilies and 11 genera with one that is fossil. The genus type is Phylloxera. The Phylloxeridae species are usually called Phylloxerans or Phylloxerids.
Aphis craccivora, variously known as the cowpea aphid, groundnut aphid or black legume aphid, is a true bug in the family Aphididae. Originally of probable Palearctic origin, it is now an invasive species of cosmopolitan distribution.
Lipaphis erysimi is a species of aphid of the family Aphididae. Its common names include mustard aphid and turnip aphid. It is found in most temperate and tropical areas of the world and feeds only on cruciferous plants. The insects are almost exclusively female and are very prolific, with wingless females producing around one hundred young during a lifespan of a few weeks.
Acyrthosiphon kondoi, the blue alfalfa aphid or bluegreen aphid, is an aphid in the superfamily Aphidoidea in the order Hemiptera. It is a true bug and sucks sap from leguminous plants, particularly alfalfa.
The hawthorn-carrot aphid,, also known as Dysaphis (Dysaphis) crataegi, is an aphid in the superfamily Aphidoidea in the order Hemiptera. It is a true bug and sucks sap from plants.
Nylanderia pygmaea is an extinct species of formicid in the ant subfamily Formicinae known from fossils found in the Baltic region.
Metopolophium dirhodum, the rose-grain aphid or rose-grass aphid, is a species of sap-sucking insect in the family Aphididae found worldwide. Its primary host is rose, and its secondary host is a grass, including cereals such as wheat, barley, oats and rye. It is an important vector of the barley yellow dwarf virus (BYDV) which causes serious reductions in yields of affected crops.
Cryptomyzus ribis is a species of true bug found in Europe and described by the Swedish taxonomist, Carl Linnaeus in 1758. The larvae feed on the leaves of current bushes, especially red currant, creating abnormal plant growths, known as galls.
