UV-reflective Mulch Research Articles

Water Use Efficiency in Young Citrus Trees on Metalized UV Reflective Mulch Compared to Bare Ground

A precise estimation of plant water use is crucial for efficient irrigation management and understanding of plant–water interactions. Metalized-polyethylene mulch as a ground cover, combined with irrigation management, can improve water and fertilizer use, efficiency growth, and yield of young citrus trees, compared to bare ground. Thus, a study was undertaken to (i) compare daily water use, using the stem heat balance (SHB) method on ≤4-year-old citrus trees using three irrigation methods, and (ii) to determine soil moisture content, as well as total available soil water (TASW) in the irrigated zone. Three irrigation methods, regulated deficit irrigation (RDI), conventional drip irrigation (CD), and microsprinkler irrigation (MS), were applied on two sandy soils in central and southwest Florida with treatments further split between trees grown on 2.4 m mulched beds (M) and bare ground (NM) to form a factorial design. Measurements included sap flow, canopy size, leaf area index (LAI) and soil moisture. The result of this study shows greater values for the trunk cross-sectional area, canopy volume and LAI for both mulch treatments, in comparison to bare ground treatments. The sap flow data suggest that RDI resulted in higher water use than both CD and MS. The hourly sap flow was 120, 99 and 163% greater in M-RDI than M-CD, NM-CD and NM-MS, respectively. Mulched ground cover showed a higher soil moisture average at all soil layers (8-, 15- and 45-cm depth). For instance, the mulched ground cover showed higher soil moisture (37%) at a 15 cm depth at the Entisol site, followed by 30% at a 45 cm depth and 25.3% at depth 45 cm for the Spodosol site. The TASW values varied between 100 to 136% for both mulch and bare ground treatments. The irrigation systems used showed water contents close to field capacity, indicating that water was not limiting despite the different irrigation schedules. The high-water uptake is ascribed to frequent irrigation applications and pulses, and improved water distribution in the irrigated zone as a result of the mulch. These findings demonstrate the potential of metalized-polyethylene mulch and regulated drip irrigation to enhance water use efficiency.

Combining Cultural Tactics and Insecticides for the Management of the Sweetpotato Whitefly, Bemisia tabaci MEAM1, and Viruses in Yellow Squash

The sweetpotato whitefly, Bemisia tabaci MEAM1 Gennadius (Hemiptera: Aleyrodidae), and the complex of viruses it transmits are major limiting factors to squash production in the southeastern United States. At this time, insecticides are extensively relied upon for the management of whiteflies and, indirectly, whitefly-transmitted viruses. The development of a multi-faceted, integrated pest management (IPM) program is needed to increase the sustainability and profitability of squash production. Experiments in 2018 and 2019 evaluated the effects of insect exclusion netting (IEN) in combination with selected pesticides on whitefly population dynamics and virus incidence in greenhouse-grown squash seedlings. Field experiments from 2018 to 2021 evaluated the effects of mulch type (UV-reflective mulch, live mulch, and white plastic mulch), row covers, and insecticides on whitefly population dynamics, silver leaf disorder (SSL) intensity, virus symptom severity, and marketable yield. IEN significantly reduced whiteflies and virus incidence on squash seedlings in the greenhouse study. In the field mulch study, lower whitefly abundance and SSL intensity, as well as reduced virus symptom severity, were observed in plots with reflective mulch compared with white plastic or live mulch. In the insecticide/row cover study, whitefly abundance, SSL intensity, and virus symptom severity were lowest in the row cover and cyantraniliprole- and flupyradifurone-treated plots. Field plots with row covers and those with UV-reflective mulch consistently produced the greatest marketable yields. These findings demonstrate that growers can reduce whitefly and virus pressure and preserve yields in squash production in the southeastern United States by combining cultural and chemical tactics, including row covers, UV-reflective mulch, and select insecticides.

Within-plant Distributions and Density of Amblyseius swirskii (Acari: Phytoseiidae) as Influenced by Interactions Between Plastic Mulch and Vegetable Crop Species

Plastic mulch of different colors and ultraviolet (UV) reflectivity individually or combined with released arthropod predators is an important component of an integrated pest management strategy. In 2015 and 2016, we evaluated the density and within-plant distribution of a released predatory mite, Amblyseius swirskii Athius-Henriot (Acari: Phytoseiidae) in snap bean (Phaseolus vulgaris L.), cucumber (Cucumis sativus L.), yellow squash (Cucurbita pepo L.), eggplant (Solanum melongena L.), Jalapeno pepper (Capsicum annuum L.), and tomato (Solanum lycopersicum L.) grown on different plastic mulches. The mulch treatments evaluated were: metalized top and black bottom, metalized top and white bottom, black-on-black, black-on-white, white-on-black, and bare soil with no mulch. Crop species had a significant effect on the density of A. swirskii. Eggplant and cucumber had higher numbers of A. swirskii than the other crops tested in 2015. In 2016, the density of A. swirskii was higher on eggplant than on cucumber. There was a variation in the distribution of A. swirskii in different strata of the plant canopies with the highest number in the bottom stratum of each crop, which was positively correlated with the population of Thrips palmi Karny (Thysanoptera: Thripidae). Mulch type had no effect on the density or distribution of A. swirskii in any strata of any of the crops tested. The results of this study indicate that releasing A. swirskii is compatible with the use of UV-reflective mulch. This information about host preference and within-plant distribution of A. swirskii should be of value in pest management programs for the crops studied.

Outbreaks of Tomato Chlorotic Spot Tospovirus in Commercial Tomato Fields and Effectiveness of Different Management Measures in South Florida

Tomato chlorotic spot tospovirus (TCSV) is an emerging tospovirus in south Florida. TCSV has caused significant damage to tomato production since its discovery in the United States in 2012. Effective measures for managing tomato chlorotic spot (TCS) disease have not been determined in commercial production fields except for planting resistant/tolerant tomato cultivars. In this study, the distribution of TCS in commercial tomato fields was investigated, and the two grower-implemented control measures, the use of resistant tomato cultivars and UV-reflective plastic mulch to repel TCSV vectors, were evaluated for any effect on the incidence of infection or disease when a severe outbreak occurred during the 2018 to 2019 season. A gradient TCS disease was found throughout the field planted with the susceptible cultivar ‘Sanibel’, suggesting a dispersal of the vectors from external sources and the influence of wind direction on disease distribution. Results from the surveys showed that the resistant/tolerant tomato cultivar ‘Red Bounty’ had significantly (P < 0.05) lower infection with TCSV compared with the susceptible cultivar Sanibel on the same type of plastic mulch in adjacent fields. UV-reflective plastic mulch significantly reduced TCS incidence in the susceptible tomato cultivar Sanibel compared with the standard white plastic mulch. This study provided first-hand support for recommendations to effectively manage TCS in tomato fields in south Florida.

Evaluation of a Push-Pull System for the Management of Frankliniella Species (Thysanoptera: Thripidae) in Tomato.

A push-pull strategy for reducing populations of the thrips Frankliniella occidentalis (Pergande), F. bispinosa (Morgan) and F. tritici (Fitch) in tomato was evaluated. Push components consisted of ultraviolet (UV)-reflective mulch and foliar applications of kaolin and the pull component consisted of the companion plant Bidens alba (L.). Replicated field experiments were conducted in 2011 and 2012. Adult and larval thrips were reduced by UV-reflective mulch during early and mid-flowering of tomato. Spray applications of kaolin were effective in reducing adult and larval thrips during early, mid- and late-flowering. The pull effects of the B. alba companion plants were additive and sometimes interactive with the push effects of UV-reflective mulch and kaolin in reducing the adult males of each thrips species and the females of F. bispinosa. The strategy was not effective in reducing the adult females of F. tritici and F. occidentalis. In addition to attracting the Frankliniella species adults, the companion plants were hosts for the thrips predator Orius insidiosus (Say). The companion plants combined with UV-reflective mulch and kaolin proved effective as a push-pull system for suppressing flower thrips, including F. occidentalis which is a serious pest of tomato worldwide.

Evaluation of a push-pull strategy for the management of Frankliniella bispinosa (Thysanoptera: Thripidae) in bell peppers.

A push-pull strategy for managing the anthophilous Frankliniella bispinosa (Morgan) in pepper and increasing conservation biological control was evaluated. Push components of ultraviolet (UV)-reflective mulch and foliar applications of kaolin and the pull component of sunflower companion plants were evaluated in replicated field experiments in 2011 and 2012. Adult F. bispinosa rapidly colonized and reproduced in the peppers and sunflowers during early flowering, but populations declined later, as numbers of the predatory Orius insidiosus (Say) and Orius pumilio (Champion) increased in both hosts. Numbers of F. bispinosa were reduced by kaolin during early pepper flowering. Thrips numbers were increased on some of the later sample dates, apparently due to reduced predation that resulted from negative effects of kaolin and UV-reflective mulch on Orius populations. Numbers of thrips increased in peppers with companion plants during the first week of flowering each year, followed by declines in thrips numbers during the next 2 wk in 2011. There was little effect each year of the companion plants on the numbers of Orius in the pepper flowers. There was one date in 2011 and no dates in 2012 in which UV-reflective mulch or kaolin acted in concert with the presence of the companion plants to reduce thrips numbers in the main crop of pepper. Yield effects were not attributed to thrips damage. We conclude that sunflower companion plants did not act additively or synergistically with kaolin or UV-reflective mulch to reduce thrips and increase Orius populations in pepper.

Effect of living (buckwheat) and UV reflective mulches with and without imidacloprid on whiteflies, aphids and marketable yields of zucchini squash

The silverleaf whitefly, B biotype of the sweetpotato whitefly, Bemisia tabaci Gennadius also known as B. argentifolii Bellows and Perring, and the melon aphid, Aphis gossypii Glover, are key pests of zucchini squash in Florida. The use of mulches, living or synthetic, is one of the tactics that could be used to suppress whitefly and aphid populations and their associated transmitted viruses. Buckwheat, Fagopyrum esculentum Moench – a living mulch, and a synthetic, UV reflective mulch, were evaluated alone or in combination with a reduced-risk insecticide, imidacloprid Admire® 2F in two field experiments carried out during the Autumn of 2005 and 2006. Four 80-m2 plots were used for each treatment with standard white mulch as a control in a randomized complete block design. Imidacloprid was applied at planting and buckwheat mulch was planted approximately 2 weeks before the squash was seeded. Addition of imidacloprid to the mulches significantly reduced the number of whiteflies and apterous aphids in 2005 but not in 2006. In 2005, there were treatment differences on natural enemies' abundances where more natural enemies were recorded within buckwheat mulch than reflective mulch. Squash within synthetic mulches resulted in significantly higher yields than those grown with living mulch. We conclude that imidacloprid can be used with the mulches to manage whiteflies and aphids in zucchini squash when the pest populations are high, but this may not necessarily translate in economic benefits in terms of yields.

INTEGRATED MANAGEMENT OF VIRAL DISEASES IN FIELD-GROWN TOMATOES IN SOUTHERN ITALY

Tomato spotted wilt virus (TSWV) is a Tospovirus affecting field tomato crops worldwide. The virus is transmitted by some species of thrips. The most damaging vectors in Italy are Frankliniella occidentalis and Thrips tabaci. Only the first instar larvae can acquire the virus from an infected plant. After acquisition, the virus replicates in the vector, and the viruliferous thrips is capable of transmission for the duration of its life. Apart from TSWV, other serious threats for tomato production in Italy are the aphid transmitted Cucumber mosaic virus (CMV) and Potato virus Y (PVY), both with necrotic and non necrotic variants. Epidemics caused by TSWV, PVY and CMV occur regularly in southern Italy, where hundreds of millions of tomato plants are grown commercially every year. Insecticides applied on a calendar basis for insect control are not very effective in preventing these vector-borne viral diseases because the viruses can be transmitted to the plant before insects (thrips and aphids) are killed by insecticides. Field experiments were conducted during summer of 2005 and 2006 in the main tomato growing area of the Basilicata region, Lavello (PZ), to determine the separate and integrated effects of UV-reflective mulch (UVRM), Acibenzolar-S-methyl (Actigard) and insecticides for the management of vectors and diseases on tomato. TSW disease pressure was great during 2005 summer but very low in 2006. Disease incidence was measured as percentages of plants infected with each of the three viruses. Aphid populations were evaluated by counting the number of aphids on sampled tomato shoots on one third of the plants on each plot. Tomato yield was evaluated from one third of the plants on each plot. Statistical analysis (analysis of variance) was performed using the SYSTAT 9 Software. The UVRM alone was effective in reducing disease incidence both for aphids and thrips transmitted viruses. A synergistic effect of Actigard with UVRM was observed against the three viruses. The use of the insecticides resulted in a further reduction in the incidence of the three viral diseases on UVRM, and reduced incidence of diseases caused by CMV and PVY in the black mulch and bare soil plots. The combination of UV-reflective mulch, acibenzolar-S-methyl, and insecticides was the most effective in reducing tomato spotted wilt incidence in tomato. The UV-reflective mulch was very effective in delaying and reducing colonization of aphids and subsequent virus incidence. There was no significant difference in the tomato yield between UVRM and black mulch plots. In contrast, yield was strongly reduced in the bare soil plots.

Reflective Plastic Mulch but not a Resistance-Inducing Treatment Reduced Watermelon Mosaic Virus Incidence and Yield Losses in Squash

Plant viruses, especially those transmitted by aphids in a nonpersistent manner, cause significant yield losses in cucurbit crops. Studies have shown that UV-reflective mulches can reduce insects from entering a crop with coincidental reductions in virus incidence. Treatment of plants with various forms of resistance-inducing agents have also shown promise for their ability to reduce plant virus incidence and associated losses. In this article, we describe a two-trial study that evaluated the integration of UV-reflective plastic mulch and a commercially available resistance-inducing treatment, BioYield™, to reduce the incidence and disease-related yield losses in summer squash [Cucurbita pepo var. melopepo (L.) Alef.] caused by the aphid-borne plant virus, Watermelon mosaic virus (WMV). In the spring trial, there was significantly reduced WMV incidence and whole treatment average enzyme-linked immunosorbent assay (ELISA) values among squash plants grown on silver-on-black (UV-reflective) mulch compared with plants grown on nonreflective black mulch. Significantly greater squash fruit yields were obtained for plants grown on the silver-on-black mulch relative to the black mulch treatment. In the fall trial, highly UV-reflective silver mulch was used in addition to silver-on-black and black mulches. WMV incidence and whole treatment average ELISA values were significantly lower for squash plants in the silver mulch treatment compared with silver-on-black and black mulch treatments. The silver-on-black treatment resulted in lower WMV incidence and whole treatment average ELISA values compared with the black mulch treatment. Squash plant yields were significantly greater for plants in the silver-on-black mulch treatment than for those in the silver or black mulch treatments. Treatment of squash plants with BioYield™ did not reduce virus incidence, or whole treatment average ELISA values, nor did it result in higher squash fruit yields compared with the nontreated control in spring or fall trials.

Suppression of Whiteflies, Bemisia tabaci (Hemiptera: Aleyrodidae) and Incidence ofCucurbit Leaf Crumple Virus, a Whitefly-transmitted Virus of Zucchini Squash New to Florida, with Mulches and Imidacloprid

Abstract The sweetpotato whitefly, Bemisia tabaci B biotype (Gennadius) (Homoptera: Aleyrodidae) also known as Bemisia argentifolii (Bellows and Perring) is a key pest in zucchini squash (Cucurbita pepo L.) causing both direct and indirect damage. A field experiment was conducted in the fall of 2005 and repeated in the fall of 2006 to investigate the effect of mulches alone or in combination with a reduced-risk insecticide, imidacloprid (Admire® 2F) on whiteflies and related problems in zucchini squash. UV-reflective mulch and the living mulch, buckwheat (Fagopyrum esculentum Moench), with and without imidacloprid, were evaluated in a randomized complete block design with 4 replications. White mulch (standard) was included as a control in the experiment. Mulches in combination with imidacloprid resulted in fewer whiteflies per leaf than those without imidacloprid in 2005 and 2006. More whiteflies were recorded on zucchini plants growing on white synthetic mulch than all other treatments in both years. In ...

Integrated Management of Tomato Spotted Wilt on Field-Grown Tomatoes.

Epidemics of spotted wilt caused by Tomato spotted wilt virus (TSWV) vectored by Frankliniella occidentalis and possibly other thrips species occur regularly in tomato in the southeastern United States. Field experiments were conducted to determine the effects of UV-reflective mulch, acibenzolar-S-methyl (plant activator), and insecticides on progress of tomato spotted wilt incidence and population dynamics of flower thrips (including F. occidentalis, F. tritici, and F. bispinosa). Whole plots of tomatoes grown on UV-reflective and black polyethylene mulch were divided into subplots of acibenzolar-S-methyl and no acibenzolar-S-methyl, and sub-subplots of insecticide and no insecticide for thrips control. The UV-reflective mulch was more effective than black polyethylene mulch each year in reducing colonization of thrips in May and the consequent primary infections of tomato spotted wilt. Application of acibenzolar-S-methyl further reduced tomato spotted wilt incidence in 2000 and 2002, when disease pressure was great. Reproduction of thrips on tomato was poor in these experiments, but their control in the insecticide-treated sub-subplots prevented secondary spread in both years. The combination of UV-reflective mulch, acibenzolar-S-methyl, and insecticides was very effective in reducing tomato spotted wilt incidence in tomato.

Integrated management tactics for Frankliniella thrips (Thysanoptera: Thripidae) in field-grown pepper.

In a 2-yr study, the impacts of different plastic soil mulches, insecticides, and predator releases on Frankliniella thrips and their natural enemies were investigated in field-grown peppers. Ultraviolet light (UV)-reflective mulch significantly reduced early season abundance of adult thrips compared with standard black plastic mulch. This difference diminished as the growing seasons progressed. Late season abundance of thrips larvae was higher in UV reflective mulch compared with black mulch plots. The abundance of the predator Orius insidiosus (Say) was significantly lower in UV-reflective mulch compared with black mulch treatments. Infection of plants with tomato spotted wilt virus, a pathogen vectored by Frankliniella occidentalis (Pergande), was <6%. In the year with the higher disease incidence (2000), UV-reflective mulch plots had significantly less disease (1.9%) compared with black mulch plots (4.4%). Yield was significantly higher in UV-reflective mulch (24,529 kg/ha) compared with black mulch (15,315 kg/ha) during this year. Effects of insecticides varied with species of thrips. Spinosad reduced abundance of F. occidentalis, but not Frankliniella tritici. In contrast, esfenvalerate and acephate reduced numbers of F. tritici and Frankliniella bispinosa, but resulted in higher populations of F. occidentalis. Spinosad was the least disruptive insecticide to populations of O. insidiosus. Releases of O. insidiosus and Geocoris punctipes (Say) reduced populations of thrips immediately after releases; naturally occurring predators probably provided late season control of thrips. Our results suggest that UV-reflective mulch, combined with early season applications of spinosad, can effectively reduce abundance of thrips in field-grown pepper.

Population Dynamics of &lt;I&gt;Frankliniella&lt;/I&gt; spp. and Tomato Spotted Wilt Incidence as Influenced by Cultural Management Tactics in Tomato

We investigated the effects of ultraviolet (UV)-reflective mulch and two rates of nitrogen fertilization on populations of Frankliniella spp. thrips and on the incidence of tomato spotted wilt in field-grown tomato in northern Florida. The higher of the two soil nitrogen fertilizer treatments significantly increased populations of Frankliniella occidentalis (Pergande), whereas mulch reflectance significantly decreased populations of F. occidentalis. Populations of Frankliniella tritici (Fitch) were decreased only by UV-reflective mulch. Decreased thrips populations in UV-reflective mulch plots were probably due to disruptions in host-finding behavior. Increased thrips populations in tomatoes treated with the higher nitrogen fertilization rate were probably due in part to increased nutrients available in flowers. Incidence of tomato spotted wilt was significantly decreased in tomatoes grown on UV-reflective mulch, whereas disease incidence was significantly greater in increased nitrogen-fertilized plots. This research reveals that cultural practices resulted in up to 45% reduction in the numbers of vector and nonvector species of flower thrips and up to 50% reduction in tomato spotted wilt.

Effect of Ultraviolet-reflective Mulches on Tomato Yields and on the Silverleaf Whitefly

Field studies were conducted for three seasons, Fall 1994, Spring 1995, and Fall 1995, on the effect of ultraviolet (UV)-reflective films (mulches) on the silverleaf whitefly (Bemisia argentifolii Bellows and Perring), the incidence of tomato mottle virus (ToMoV), and on fruit yields of staked, fresh-market tomatoes (Lycopersicon esculentum Mill.). The UV-reflective mulches were metallized aluminum (aluminum) and painted aluminum (silver) on either black or white plastic film. The aluminum and silver mulches were evaluated with and without a white (fall) or black (spring) 25-cm-wide painted band in the bed center. Controls were the conventional white (fall) or black (spring) polyethylene mulches. Highest reflected energy (μmol·m–2·s–1) to the plants at 15 cm from the mulch surface was measured on the aluminum mulch with or without a white painted band. Lowest energy was reflected from the white or black controls and from silver on black mulches with or without a black painted band. Whitefly populations in the fall were lower (P ≤ 0.05) on the aluminum than on the silver mulches. In the spring, when whitefly populations were low, whiteflies were more numerous on the black control and silver on white, than on the aluminum mulches. In the fall seasons, the proportion of plants with symptoms of ToMoV transmitted by the silverleaf whitefly were higher on the controls than on the aluminum mulch. In the spring, the proportion of plants with symptoms was not affected by mulch treatments. Yields in the fall were similar with UV-reflective or white control mulches. In the spring, fruit size and marketable yields were greater (P ≤ 0.05) on plants with silver on white mulch than on the control black mulch.

Effect of UV-reflective Mulches on Tomato Yields and on the Silverleaf Whitefly, Bemisia argentifolii (Bellows &amp; Perring)

Field studies were conducted for three seasons, Fall 1994, Spring 1995, and Fall 1995 on the effect of UV-reflective films (mulches) on fruit yields and on the silverleaf whitefly [Bemisia argentifolii (Bellows and Perring)] of staked, fresh-market tomatoes (Lycopersicon esculentum Mill). The UV-reflective mulches were metallized aluminum (ALU) and painted aluminum (PAL) on either black or white plastic film. The AL and SL mulches were evaluated with and without a white (fall) or black (spring) 25-cm-wide painted band in the bed center. Controls were the conventional white (fall) or black (spring) polyethylene mulches. Highest reflected energy (μmol·m–2·s–1) to the plants at 25 cm from the mulch surface was measured on the ALU without white painted band or on PAL on white or black mulch with white painted band. Lowest energy was reflected from the white or black controls. Whitefly populations in the fall were lower on the ALU than on the PAL mulches. In the spring, when whitefly populations were low, number of whiteflies on tomato leaves were similar with all treatments. The proportion of plants with symptoms of the silverleaf whitefly transmitted tomato mottle virus (TMoV) were highest on controls. Yields in the fall were similar with UV-reflective or with white mulch. In the spring, fruit size and marketable yields were greater (P &lt; 0.05) on plants with PAL on white plastic film without black band than on black control.

Management of Insects on Pepper and Tomato with UV-Reflective Mulches

Aluminum-painted plastic mulch, whether with the entire exposed mulch surface painted or with lateral strips painted, generally was equivalent to aluminum plastic film and superior to non-painted plastic or bare soil as to the numbers of aphids and thrips collected from water dish traps or as to the numbers of aphids on foliage. Numbers of thrips in flowers were not affected consistently by mulch treatments. Effects of the aluminum-painted mulch appeared to persist longer on pepper than on tomato probably because the pepper plants were smaller than the tomato plants and covered less of the mulch. The aluminum-painted mulch did not affect significantly the numbers of leafmines and mite colonies on tomato foliage but did result in fewer tomato plants infected with aphid-transmitted virus compared to non-painted mulch. Less virus also was observed on plants grown on aluminum-painted mulch in a commercial tomato field even though differences in the numbers of aphids on foliage were not significant relative to black mulch.