62-536: The Tule Mountains is a mountain range in Yuma County, Arizona . There is a diverse flora and fauna population within the Tule Mountains; one of the notable trees found in this mountain range is the elephant tree ( Bursera microphylla ). 32°11′09″N 113°47′38″W / 32.1858953°N 113.7938144°W / 32.1858953; -113.7938144 Yuma County, Arizona Yuma County
124-595: A brown color near hatching, within 5 to 7 days. After hatching, the whitefly nymph develops through four instar stages. The first instar , commonly called a crawler, is the only mobile nymphal stage. The first instar nymph can grow to about 0.3 millimetres ( 1 ⁄ 64 in) and is greenish in color and flat in body structure. The mobile nymph walks to find a suitable area on the leaf with adequate nutrients and molts into an immobile stage. The next three instars remain in place for 40–50 days, until molting into an adult. Silver exuvia , or shed skins are left on
186-463: A household in the county was $ 32,182, and the median income for a family was $ 34,659. Males had a median income of $ 27,390 versus $ 22,276 for females. The per capita income for the county was $ 14,802. About 15.5% of families and 19.2% of the population were below the poverty line , including 27.9% of those under age 18 and 8.7% of those age 65 or over. As of the 2010 census , there were 195,751 people, 64,767 households, and 48,976 families residing in
248-534: A minimal effect on plant and soil properties. Scientists are currently focusing on targeting the whitefly through mechanisms that do not cause pollution or contamination (i.e., mechanisms other than insecticides). It is important to be able to reduce the number of B. tabaci individuals that settle on plants to decrease plant damages such as those caused by viral transmissions. This can be accomplished by reducing settling, decreasing oviposition , and abating population development. Classical biological control has been
310-431: A pesticide free method of control of B. tabaci. The Light-Emitting Diode Equipped CC trap (LED-CC) was developed by plant physiologist Chang-Chi Chu and Thomas Henneberry. Originally, the trap was used to monitor population of silverleaf whitefly populations, but as the trap was improved it was used in control programs to limit whitefly pest populations. The trap itself includes a green LED light that attracts and traps
372-884: A year after its identification, strain B was found to have moved to tomatoes , and other fruit and vegetable crops. Within five years, the silverleaf whitefly had caused over $ 100 million in damage to agriculture in Texas and in California . Female B. tabaci will lay 50 to 400 eggs ranging from 0.10 to 0.25 millimetres ( 1 ⁄ 128 to 1 ⁄ 128 in) on the under part of leaves. Female whiteflies are diploid and emerge from fertilized eggs whereas male whiteflies are haploid and emerge from unfertilized eggs. Eggs are laid in groups, being small in size with dimensions of 0.2 millimetres ( 1 ⁄ 128 in) wide and 0.1 millimetres ( 1 ⁄ 128 in) in height. Eggs are initially whitish in color and change to
434-577: Is a county in the southwestern corner of the U.S. state of Arizona . As of the 2020 census , its population was 203,881. The county seat is Yuma . Yuma County includes the Yuma, Arizona Metropolitan Statistical Area . The county borders three states: Sonora , Mexico, to the south, and two other states to the west, across the Colorado River : California of the United States and
496-528: Is a common pest here. The county is planted with large extents of several crops which serve as hosts. Date trees ( Phoenix dactylifera ) were planted here in the 2010s. In this county, plantations suffer from the Carob Moth ( Ectomyelois ceratoniae ) and the Banks Grass Mite ( Oligonychus pratensis ). Leaders in the county are aware their economy is tied to that of Mexican states on
558-514: Is a result of the U.S. economic downturn and other systemic factors". The Greater Yuma Economic Development Corp anticipates many agricultural jobs in the county will soon transition to robotics . The Board of Supervisors is the governing body of the county and a number of special districts. The board has members from five districts. The Board adopts ordinances, establishes programs, levies taxes, appropriates funds, appoints certain officials, and zones property and regulates development in
620-442: Is also highly effective in controlling the number of whiteflies. Other natural oils such as cottonseed, castor, peanut, soybean, and sunflower can be effective. Peanut oil was the most effective out of this group in reducing the population. All of these oils cause direct mortality to immature life stages of the silverleaf whitefly on contact and reduce settling and ovipositon by adults when sprayed on plant leaves. The oil extracted from
682-508: Is essentially a crippling disease of the watermelon, which leads to the vine of the watermelon to collapse, causing the death of the watermelon before harvest. Kousik and pathologist Scott Adkins at ARS Subtropical Plant Pathology Research Unit worked together in screening the watermelon germplasm for resistance to SqVYV as to search for potential sources of resistance in wild-type watermelon. Kousik examined different combinations of insecticides and silver plastic mulch that could be used to reduce
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#1732791133443744-563: Is in the west, and northwestern regions of the north–south Sonoran Desert that extends through Sonora state of Mexico to the border of northern Sinaloa state. West of the county across the Colorado River in southeast California is the Colorado Desert , (a northwestern subregion of the Sonoran Desert). North of the county, with La Paz County the regions merge into the southeastern Mojave Desert . Southwest of Yuma County,
806-410: Is only able to control the species in small experimental greenhouses. The species Encarsia formosa works much better at controlling the whitefly species Trialeurodes vaporariorum than it does B. tabaci . Eretmocerus sp. has been found more successful at B. tabaci than the E. formosa "Beltsville Strain". The wasps are faster at searching for patches of host nymphs are consistent at controlling
868-419: Is only an effective biological control agent in conditions of low temperatures (maximum of 20 °C (68 °F)) and a humidity level greater than 96%. Not enough studies have been conducted to show the productiveness of fungal pathogen in the real world environment. Much of the success of this biological control on B. tabaci has been conducted in the laboratory. However, it can be concluded though that when
930-776: Is the entirety of Northwest Mexico, at the north shoreline of the Gulf of California , and the outlet of the Colorado River into the Colorado River Delta region, now altered with lack of freshwater inputs. Notable mountains in Yuma County include the Gila Mountains and the Tule Mountains . As of the census of 2000, there were 160,026 people, 53,848 households, and 41,678 families residing in
992-434: Is the highest crop producer in the state by dollar value per year. Yuma County tops the list for the categories of vegetables + melons + potatoes + sweet potatoes at $ 782,293,000, and fruits + tree nuts + berries at $ 62,499,000. Overall this is the second (to Maricopa ) producing county for all agricultural products at $ 1,143,068,000 per year and for organic production . Almost all of the dates ( Phoenix dactylifera ) in
1054-441: Is the use of fungal pathogens. The most commonly known pathogens to the whitefly pest are Paecilomyces fumosoroseus , Aschersonia aleyrodis , Verticillium lecanii , and Beauveria bassiana . When spore solutions of V. lecanii are sprayed on eggs of B. tabaci approximately 89% to 90% of these eggs are killed. Some strains of whitefly have developed resistance to its fungal pathogens including V. lecanii . B. bassiana
1116-477: The X-ray crystal structure for the 1Z5X ligand-binding domain of the B. tabaci EcR. Multiple methods of control can be used to combat these prevalent agricultural pests. Some major control methods include, application of oils, use of natural enemies such as Aphelinidae parasitoids , employment of trap crops , release of insect growth regulators, and implementation of traps. Most of these control tools have
1178-486: The insect growth regulator pyriproxyfen has been found successful in reducing whitefly populations on c urbit plants including zucchini squash, cucumber, and pumpkin. This hormone is a juvenile hormone analogue , which affects hormonal balance and chitin in immature insects, and causes deformation and death during molting and pupation . This insect growth regulator does not kill adult whiteflies, and has low toxicity to mammals, fish, birds and bumblebees. Traps offer
1240-532: The phloem or lower leaf surfaces with its mouth and removing nutrients. Affected areas of the plant may develop chlorotic spots, whither, or drop leaves. Whiteflies also produce a sticky substance called honeydew , which is left behind on the host. Honeydew can induce the growth of sooty molds , which can then reduce the plants ability to absorb light. This results in slower growth, lower yield, and poor quality plants. It also requires that crops be thoroughly washed after harvesting, which raises processing costs for
1302-599: The 1980s. Scientists speculate that this pest was introduced via infested ornamental plants brought into the United States at this time. Florida's poinsettia greenhouses were crippled by the pest beginning in 1986, and by 1991, the infestation had spread through Georgia, Louisiana, Texas, New Mexico, and Arizona to plague growers in California. California produces approximately 90% of the United States’ winter vegetable crop, and has incurred an estimated $ 500 million in crop damage due to silverleaf whitefly populations. Across
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#17327911334431364-566: The Board than Republicans for the first time since 2004. However, their margins of victory have been reduced in recent years as the county has rapidly grown in population and become majority-Hispanic. Donald Trump only won the county by 560 votes over Hillary Clinton in the presidential election of 2016 . However, Trump's margin did improve to over 4,000 votes as he won the county again in 2020 over Joe Biden . In 2024 , Trump won Yuma County by over 20 percentage points against Kamala Harris ,
1426-591: The Mexican state of Baja California . Being 63.8% Hispanic in 2020, Yuma is Arizona's largest majority-Hispanic county . Long settled by Native Americans of indigenous cultures for thousands of years, this area was controlled by the Spanish Empire in the colonial era. In the 19th century, it was part of independent Mexico before the Mexican–American War and Gadsden Purchase . Yuma County
1488-487: The United States illegally pass through Yuma County. From October 2004 to July 2005, some 124,400 undocumented foreign nationals were apprehended in the area, a 46% increase over the previous year. In 2014, however, only 5,902 people were apprehended. The report from the Congressional Research Service stated, "...it is unclear how much of the drop-off is due to increased enforcement and how much
1550-485: The Western United States to control B. tabaci . However, differences in climate preference by these wasps reduced their effect. The best studied of these whitefly parasitoids are Encarsia formosa and Eretmocerus eremicus , both of which are commercially available. The Encarsia formosa "Beltsville Strain", however, has been unsuccessful in control B. tabaci biotype B in commercial greenhouses; it
1612-484: The adult silverleaf whitefly. Thus, when planting seeds, placing a reflective polyethylene mulch on planting beds will significantly reduce the rate of colonization. Cultural controls are very important to crops such as vegetables and fruit. For example, in the family Cucurbitaceae, vegetables such as watermelon and squash contract squash vein yellowing virus (SqVYV) by the silverleaf whitefly. The SqVYV virus discovered by plant pathologist Benny Bruton and Shaker Kousik
1674-1000: The agricultural industry, this pest is thought to cost the state $ 774 million in private sector plant sales, 12,540 jobs, and $ 112.5 million in personal income. On a national scale, the United States has suffered crop and ornamental plant damages in excess of $ 1 billion. This species of whitefly is a particularly devastating pest because it feeds on over 500 plant species. Common hosts are agricultural crops including tomatoes, squash, broccoli, cauliflower, cabbage, melons, cotton, carrots, sweet potato, cucumber, and pumpkin, and ornamental plants such as poinsettia , crepe myrtle , garden roses , lantana , and lilies . It can cause specific damage to certain host plants, like "silverleaf" on squash, irregular ripening of tomatoes, whitestalk in broccoli and cauliflower, white stem in poinsettia, and light root in carrots. B. tabaci like all arthropods has ecdysone receptors (EcRs) which may be useful for insecticide development . Carmichael et al. , 2005 presents
1736-487: The amount of B. tabaci infected plants. Planting different host crops away from each other will decrease the number of plants the flies will be able to infect. Thus, the best control is to maximize the distance and time interval between host crops. Good sanitation in winter and spring crops is also required for the maintenance and control of the fly population. Weeds and host crop residues must be removed immediately to avoid infestation. Silver/aluminum cover mulches can repel
1798-442: The best long-term, sustainable solution to controlling these exotic pests. However, success of this method can be unpredictable. Entomologists with the U.S. Arid-Land Agricultural Research Center identified the most common causes of death of the whitefly as predation by other insects, parasitism, and weather induced dislodgement. They emphasize the importance of exploiting the use of natural predators and have identified predators by
1860-654: The best performance by a Republican since Ronald Reagan in 1984 . According to the United States Census Bureau , the county has an area of 5,519 square miles (14,290 km ), of which 5,514 square miles (14,280 km ) is land and 5.1 square miles (13 km ) (0.1%) is water. The lowest point in the state of Arizona is on the Colorado River in San Luis in Yuma County, where it flows out of Arizona and into Sonora in Mexico . Yuma County
1922-571: The contents of the silverleaf whitefly by piercing its exoskeleton. Adult and larval stages of this beetle feed on all life stages of the pest. C. rufilabris is only able to feed on the immature stages or the larval stages of B. tabaci . Another natural enemy of the whitefly are parasitoids , which kill their host once their development has been completed. Parasitoids in the families Platygasteridae , Aphelinidae , and Eulophidae are known to attack whiteflies. Establishment of several Old World species of Eretmocerus wasps has been attempted in
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1984-408: The control of B. tabaci. Currently, the most effective oil in the market is the ultra-fine oil , which is a paraffinic oil product that reduces the settlement of the adult flies, decreases oviposition , and abates the transmission of the tomato yellow leaf curl virus . The effect of ultra-fine oil can be strengthened through the combination with oils such as limonene or citronellal . Olive oil
2046-462: The county produced vegetables worth $ 782,293,000, ranking first in the state and third in the entire country, from 107,908 acres (43,669 ha). Fruits brought $ 62,499,000, also first in the state, 56th out of >3000 counties in the country. Jojoba ( Simmondsia chinensis ) is a valuable native crop here. From here it has also been introduced into cultivation in other countries. The Sweetpotato Whitefly (Silverleaf Whitefly, Bemisia tabaci )
2108-455: The county. The population density was 35.5 inhabitants per square mile (13.7 inhabitants/km ). There were 87,850 housing units at an average density of 15.9 units per square mile (6.1 units/km ). The racial makeup of the county was 70.4% white, 2.0% black or African American, 1.6% American Indian, 1.2% Asian, 0.2% Pacific islander, 20.8% from other races, and 3.8% from two or more races. Those of Hispanic or Latino origin made up 59.7% of
2170-405: The county. The population density was 29 people per square mile (11 people/km ). There were 74,140 housing units at an average density of 13 units per square mile (5.0 units/km ). The county's racial makeup was 68.3% White , 2.2% Black or African American , 1.6% Native American , 0.9% Asian , 0.1% Pacific Islander , 23.6% from other races , and 3.2% from two or more races. 50.5% of
2232-419: The families Phytoseiidae , Coccinellidae , Syrphidae , Anthocoridae , Nabidae , and Miridae , Chrysopidae and Coniopterygidae . There are currently four species of predators that are commercially available for control of B. tabaci: Delphastus pusillus , Macrolophus caliginosus , Chrysoperla carnea , and C. rufilabris . D. pusillus is a species of small, shiny, black beetle which sucks out
2294-514: The following table is based on the 2010 census of Yuma County. † county seat 32°47′13″N 113°58′58″W / 32.78694°N 113.98278°W / 32.78694; -113.98278 Bemisia tabaci Bemisia argentifolii Bellows & Perring The silverleaf whitefly ( Bemisia tabaci , also informally referred to as the sweet potato whitefly ) is one of several species of whitefly that are currently important agricultural pests . A review in 2011 concluded that
2356-429: The fungal pathogen is combined with an insecticide, the synergistic effect of the two will induce a higher mortality rate of the whitefly. P. fumosoroseus has a broad host range but can attack silverleaf whiteflies at a variety of life stages and these include eggs, nymphs, pupae, and adults stages. On the other hand, A. aleyrodis only infects and destroys nymphs and pupae. Natural oils are another important tool in
2418-436: The grower. The silverleaf whitefly is also a notorious vector for plant disease. It has transmitted gemniviruses including lettuce infectious yellows virus , tomato yellow leaf curl virus , and African cassava mosaic virus for years and over many continents and is now a vector for cassava brown streak virus disease . Bemisia tabaci became a serious issue in crops across the southwestern United States and Mexico in
2480-519: The leaves. The immobile instars appear opaquely white. Nymphs feed by stabbing into the plant with their mouth-parts and sucking up plant juices. After the fourth instar, the nymph transforms into a pupal stage where the eyes become a deep red color, the body color becomes yellow, and the body structure thickens. This is not a true pupal stage, as is found in the Holometabola , but is similar in function. Adult whiteflies are approximately four times
2542-662: The other side of the border; both have to be considered. "There are automotive plants in Ciudad Juárez, across from El Paso; aerospace plants in Mexicali, southwest of Yuma; and medical devices’ manufacturers in Tijuana, near San Diego. On the American side, there is a mix of retail stores, warehouses and trucking companies..." Because of Yuma County's location along the U.S.-Mexico border , large numbers of aliens entering
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2604-402: The pests, but in numbers that reflected the shrinking population of pests. If natural enemies are not able to control the pest population at low levels due to a significant increase in pest, an insecticide compatible with the biological control agent could be used to assist in reducing the pest population to low levels again. Another natural mechanism of controlling the population of B. tabaci
2666-449: The population were Hispanic or Latino of any race. 43.7% reported speaking Spanish at home Language Map Data Center . There were 53,848 households, out of which 36.9% had children under the age of 18 living with them, 62.3% were married couples living together, 11.2% had a female householder with no husband present, and 22.6% were non-families. 18.5% of all households were made up of individuals, and 8.9% had someone living alone who
2728-405: The population. A variable release strategy of parasitoids has been found successfully able to control populations of B. tabaci . This was done by releasing six female parasitoids per week for the first half of the growing season, and only one female per week for the remaining of the season. This improved the effectiveness of the parasitoid wasps by ensuring they were continuously available to attack
2790-420: The population. In terms of ancestry, 10.6% were German , 7.4% were English , 6.9% were Irish , and 3.2% were American . Of the 64,767 households, 41.1% had children under the age of 18 living with them, 56.8% were married couples living together, 13.8% had a female householder with no husband present, 24.4% were non-families, and 19.6% of all households were made up of individuals. The average household size
2852-428: The seeds of sugar apple has also been found effective against the whitefly. This oil causes the silverleaf whitefly nymph to shrink in size and therefore detach from the tomato plant, leading to starvation. Sugar apple seed oil is not phytotoxic to tomato plants of any concentrations and reduces the survival rate of the pest. Insecticides can be costly, and have an increasing risk of resistance by whiteflies. However,
2914-426: The silverleaf whitefly is actually a species complex containing at least 40 morphologically indistinguishable species. The silverleaf whitefly thrives worldwide in tropical, subtropical, and less predominately in temperate habitats. Cold temperatures kill both the adults and the nymphs of the species. The silverleaf whitefly can be confused with other insects such as the common fruitfly , but with close inspection,
2976-401: The size of the egg, with light yellow bodies and white wings, which is attributed by the secretion of wax across its wings and body. Adult silverleaf whiteflies can reach up to 0.9 millimetres ( 5 ⁄ 128 in) in length. While feeding or resting the whitefly adult folds its wings tent-like over its body. Research indicates that the silverleaf whitefly likely came from India. Since
3038-447: The spread of dangerous plant viruses, which these insects are notorious for transmitting. Plants which are affected by the whitefly include: tomatoes , squash , poinsettia , cucumber , eggplants , okra , beans , and cotton . Other common plant damages of whitefly include: removing plant sap, breakdown of the leaves of the plant, and leaf shedding. The silverleaf whitefly is an invasive agricultural pest in many locations around
3100-417: The state are grown here, about 10 million pounds (4,500 metric tons; 5,000 short tons) worth $ 35 million per year. This is the second highest citrus producer behind Maricopa, a distant second in grapefruit , limes , and oranges but producing far more lemons . Some olives, clingstone peaches , and plums are grown here. Yuma County produces almost all of the vegetable seed grown in
3162-482: The state. The average farmer age is the lowest in the state, at 56.6 years. During the winter agricultural season from November to March, some 40,000 Mexican workers cross the border daily to work in United States fields. The area is watered by the Colorado River , and the sector supplies a large part of the US leafy vegetables. The Yuma Lettuce Days festival and agritourism is connected to Yuma agriculture. In 2017
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#17327911334433224-445: The tomato yellow curl leaf virus can be controlled and limited. Scientific experiments show in the fields that growing squash crops around the areas where tomato plants can be found is a useful manipulation in regulating the silverleaf whitefly population as well as the transmission of TYLCV. Other plants that can serve as trap crops include cantaloupe and cucumber. Through a cultural control method , different planting areas can limit
3286-495: The unincorporated area. In addition, members of the Board represent the county on numerous intergovernmental agencies. In Arizona's first 52 years as a state, Yuma County was a primarily Democratic county, only voting for the Republican candidates four times in presidential elections prior to 1968. From 1968 onward, it has consistently voted for Republican presidential candidates. In 2016, county voters elected more Democrats to
3348-595: The use of enzyme-linked immune sorbent assay ( ELISA ). It was found that the use of the biological controls and insect growth regulators produces a higher predator-to-prey ratio. Insect growth regulators, such as buprofezin and pyriproxyfen , conserve natural predators compared to conventional insecticides , which can indiscriminately kill both predator and pest populations. Predators , parasitoids , and pathogens specific to whiteflies can keep populations under control. Species in eight arthropod orders are known to be predators of B. tabaci. These include members of
3410-550: The whiteflies. The LED device works best at night, and is inexpensive and durable. In addition, the LED does not harm predators and parasitoids of the whitefly. Another technique used to reduce virus damage include the use of floating row covers, which are covers used to keep plants from exposure from pests. Field studies conducted in Australia have shown that the use of floating row covers coupled with insect growth regulators increase
3472-439: The whitefly is predominately associated with areas exhibiting tropical / subtropical climates, the focus shifts to how these insects attained access to crops in habitats with temperate climates. One hypothesis suggests that the transfer of decorative plants from tropical regions may have aided in the spread of the silverleaf whiteflies to temperate environments. The ability of the whitefly to adapt to various plants facilitates
3534-495: The whitefly is slightly smaller and has a distinct wing color that helps to differentiate it from other insects. While the silverleaf whitefly had been known in the United States since 1896, in the mid-1980s an aggressive strain appeared in poinsettia crops in Florida . For convenience that strain was referred to as strain B (biotype B), to distinguish it from the milder infestation of the earlier known strain A . Less than
3596-748: The world, including in Florida and in California . The silverleaf whitefly is considered an invasive species in the United States as well as Australia , Africa , and several European countries. It was classified as an agricultural pest in Greece around 1889 and had a significant impact on tobacco crops there. The first silverleaf whitefly was found in the United States in 1897 on a crop of sweet potatoes. This tiny insect causes damage to plants through feeding and transmitting plant diseases. The silverleaf whitefly feeds on its host plants by piercing
3658-405: The yield of harvested fruit and quality and reduce virus damage to cucurbits. Another important control is the use of other crops as a source of trap crops. Squashes can act as trap crops for the silverleaf whitefly due to the flies’ attraction to these crops. Silverleaf whiteflies are actually more attracted to the squash crop than they are to the tomato plant. When squash serves as a trap crop,
3720-488: Was 2.93 and the average family size was 3.39. The median age was 33.8 years. The median income for a household in the county was $ 40,340 and the median income for a family was $ 42,718. Males had a median income of $ 36,345 versus $ 27,262 for females. The per capita income for the county was $ 18,418. About 17.6% of families and 20.9% of the population were below the poverty line , including 30.7% of those under age 18 and 12.7% of those age 65 or over. The population ranking of
3782-453: Was 65 years of age or older. The average household size was 2.86 and the average family size was 3.27. In the county, the population was spread out, with 28.9% under the age of 18, 10.0% from 18 to 24, 25.6% from 25 to 44, 18.9% from 45 to 64, and 16.5% who were 65 years of age or older. The median age was 34 years. For every 100 females there were 102.0 males. For every 100 females age 18 and over, there were 101.1 males. The median income for
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#17327911334433844-523: Was one of four original Arizona counties created by the 1st Arizona Territorial Legislature . The county territory was defined as being west of longitude 113° 20' and south of the Bill Williams River . Its original boundaries remained the same until 1982, when La Paz County was created from its northern half. The original county seat was the city of La Paz; in 1871 it was moved to Arizona City, later renamed as Yuma in 1873. This county
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