Bruce Schaffer

Verified

Bruce verified their affiliation via an institutional email.

Learn more

Verified

Bruce verified their affiliation via an institutional email.

Learn more

• PhD
• Professor at University of Florida

We tested for isotope exchange between bound (immobile) and mobile soil water, and whether there is isotope fractionation during plant water uptake. These are critical assumptions to the formulation of the ‘two water worlds’ hypothesis based on isotope profiles of soil water. In two different soil types, soil‐bound water in two sets of 19‐l pots, e...

Laurel wilt, a lethal vascular wilt disease caused by the fungus Raffaelea lauricola, affects several tree species in the Lauraceae, including three Persea species. The susceptibility to laurel wilt of two forest tree species native to the southern United States, Persea borbonia and Persea palustris, and avocado, Persea americana cv Waldin, was exa...

Vanilla planifolia is an obligate sciophyte (shade plant) with crassulacean acid metabolism (CAM) photosynthesis. Plants were grown for 12 months under black, blue, green, or red photoselective shade netting (PSN) to alter the spectral light distribution impacting the plants. Light wavelengths were measured in each treatment and plants were assesse...

Avocado (P. americana Mill.) trees are classified into three botanical races, Mexican (M), Guatemalan (G), and West Indian (WI), each distinguished by their geographical centers of origin. While avocados are considered highly sensitive to flooding stress, comparative responses of the different races to short-term flooding are not known. This study...

Most terrestrial plants are sensitive to prolonged flooding or soil salinity, and exposure to the combination of these factors generally compounds the negative effects of each one considered separately. Achachairu (Garcinia humilis, fam. Clusiaceae), a tropical fruit tree from the Bolivian Amazon, is tolerant to flooding and moderately tolerant to...

Soil salinity poses a global threat to crop production. Early understanding of plant physiological responses to salinity stress can be critical to implementing timely stress management strategies. One of the initial plant physiological responses to salinity is a reduction of transpiration. This study used papaya as a model crop to better understand...

The pepper weevil (Anthonomus eugenii) is a major pest that causes significant economic damage to several species and cultivars of pepper, including jalapeño (Capsicum annuum var. jalapeño). Protecting pepper crops from this pest often necessitates the use of chemical insecticides. To enhance control measures and mitigate the risk of insecticide re...

Selecting the right rootstock is crucial for successful fruit production and managing both biotic and abiotic stresses in commercial fruit orchards. To enhance the resilience of peach orchards, this study evaluated the physiological and biochemical responses of Prunus spp. rootstocks , ‘Flordaguard’ and ‘MP‐29,’ under normoxia (sufficient oxygen co...

Flooding and waterlogging create hypoxic or anoxic soil conditions that negatively affect the physiology of wild and cultivated tropical fruit trees. The achachairu (Garcinia humilis) is a slow-growing tropical fruit tree endemic to the Bolivian Amazon region. Like many tropical trees, G. humilis is increasingly affected by flooding events that may...

The pepper weevil (Anthonomus eugenii Cano) is a devastating pest that inflicts severe damage to pepper crops, leading to substantial economic losses. This study investigated the impact of aging on the reproductive success of the pepper weevil. Pepper weevil-infested fruit were harvested from pepper fields and subsequently transferred into an insec...

Water deficit priming through regulated deficit irrigation has been shown to be beneficial for peanut cultivation, leading to improved water‐use efficiency during the crop cycle and enhanced stress acclimation. The effects of priming using water deficit can be heritable, but little is known about stress priming effects on the physiology and growth...

Essential oil-based products with broad plant disease control claims are commercially available and may be a practical alternative to copper fungicides for crop protection in organic mango orchards. We evaluated the disease control efficacy and crop safety of thyme oil, savory oil, and tree tea oil through replicated in vitro, in vivo (detached lea...

Water stress is a major cause of yield loss in peanut cultivation. Melatonin seed priming has been used to enhance stress tolerance in several crops, but not in peanut. We investigated the impact of seed priming with melatonin on the growth, development, and drought tolerance of two peanut cultivars, TUFRunnerTM ‘511’, a drought-tolerant cultivar,...

Citrus orchards in semi-arid regions are increasingly exposed to drought conditions due to climate change. This study compared the physiological and growth responses of ‘W. Murcott’ tangor (WM) grafted onto Citrus macrophylla (M), Swingle citrumelo (SC), C-35 citrange (C35), or bitter citrandarin (C22) rootstock subjected to two irrigation treatmen...

This article provides detailed information on the achachairú’s characteristics, botany, and recommended horticultural practices for commercial growers and county and state Extension faculty in south Florida and is also applicable for homeowners and students interested in growing achachairú. Written by Federico W. Sanchez, Jonathan H. Crane, Haimano...

Background Many coastal areas of the world will be impacted by seawater intrusion inland exposing crops to increasing levels of soil salinity. Studies of salinity stress in horticultural crops, including papaya, invariably use NaCl as the salt source, which may not be indicative of seawater. Methods This study compared plant growth, physiological,...

Deficit irrigation has emerged as a viable approach to increase agricultural water productivity. The objectives of this study were to 1) develop water conservation strategies by investigating responses of green bean (Phaseolus vulgaris) and sweet corn (Zea mays var. saccharata) to four irrigation treatments and 2) evaluate the performance of the De...

The availability of timely and accurate information about plant conditions is critical for making informed decisions for maintaining or improving agricultural productivity. However, field data collection is often laborious and time-consuming, underscoring the need for accurate and efficient methods to monitor crop growth and development. Therefore,...

Salinity is a major cause of abiotic stress to crops, including papaya (Carica papaya L.), one of the most cultivated fruit crops in tropical and subtropical regions. Two experiments were conducted to assess the response of 'Red Lady' papaya plants to salinity stress. In both experiments, salt stress was imposed by adding different concentrations o...

Asian bean thrips, Megalurothrips usitatus Bagnall, are a serious pest of vegetable crops, especially leguminous crops, across the Asian continent. In Florida, it is a new invasive pest of snap beans. In 2019, it was recorded for the first time in the United States in snap bean (Phaseolus vulgaris) fields. Another thrips species, melon thrips, Thri...

Desertification is a major environmental problem in arid, semiarid, and dry sub-humid regions throughout the world, which causes considerable reductions of ecosystem services, increased food insecurity, and poverty. The influence of vegetation cover and rainfall intensity on the dynamics of water infiltration, surface runoff, and soil loss was meas...

Plant hypoxia (low-oxygen stress or oxygen deficiency stress) is due to soil waterlogging, flooding, or soil compaction. In agricultural areas that already experience hypoxia in the root zone, and in agricultural production areas where hypoxia has never been observed, the potential for soil waterlogging and/or flooding is expected to increase as re...

Understanding plants' response to different irrigation levels is essential for developing effective irrigation scheduling practices that conserve water without affecting plant growth and yield. The objective of this study was to evaluate the responses of three sweet corn (Zea mays var. saccharata) cultivars 1170, 8021, and Battalion under three irr...

Priming involves the exposure of plants to a mild stress to increase tolerance to a more intense stress in the future. Chemical priming with brassinosteroids reduces the negative effects of flooding on the physiology and survival of some plant species. Avocado trees are very susceptible to flooding, and flooding susceptibility is related to the roo...

Atriplex nummularia L. is one of the most studied halophytes in research on phytoremediation of salt-affected soils. However, the optimization of biomass requires studies that indicate the appropriate way to evaluate the photosynthesis. The objective of this study was to investigate the photosynthetic efficiency of A. nummularia irrigated with sali...

Water scarcity is a significant constraint to profitable crop production. Crop physiologists are challenged with characterizing plant stress responses non-destructively and under precisely imposed conditions to develop efficient stress management strategies. Using an integrated high-throughput system (PlantArray, Plant-Ditech Ltd.), we quantified c...

Characterization of the soil solution is of fundamental importance for monitoring plant nutrient availability, environmental contamination, and evaluation of salt-affected soils. Due to the diversity of methodologies adopted in various parts of the world, comparison of the most common extraction methods in different types of soils is warranted. Thi...

Key message Relative susceptibility to laurel wilt among clonal, non-grafted avocado trees of different ecotypes is relate to the xylem vessel diameter, with larger vessels potentially allowing more rapid movement of fungal conidia in the transpiration stream, creating a potential for faster colonization of the vascular system by the pathogen. Abs...

Aims The effect of flooding on carbohydrate and nitrogen metabolism in leaves of peach (Prunus persica cv. UFSun) trees grafted onto six different Prunus spp. rootstock cultivars with either peach or plum parentage (peach: ‘Flordaguard’, ‘Guardian’, ‘Nemaguard’, ‘P-22’; plum: ‘R5064–5’, and ‘MP-29’) were evaluated. Methods Young peach trees were d...

This article highlights the impacts of saltwater intrusion and flooding on the health of agricultural soils. It also discusses management practices to reduce the negative impacts of soil salinity due to saltwater intrusion and/or flooding. Written by Haimanote K. Bayabil, Yuncong Li, Jonathan H. Crane, Bruce Schaffer, Ashley R. Smyth, Shouan Zhang,...

Desertification is a problem in regions with arid, semi-arid and dry sub-humid climates and is characterized by the degradation of natural resources. The influence of vegetation cover and rainfall intensity on the dynamics of water infiltration, surface runoff and soil loss was measured in situ in a Desertification Zone in the semi-arid region of B...

Sorghum bicolor (L.) Moench, one of the most important dryland cereal crops, is moderately tolerant of soil salinity, a rapidly increasing agricultural problem due to inappropriate irrigation management and salt water intrusion into crop lands as a result of climate change. The mechanisms for sorghum’s tolerance of high soil salinity have not been...

Root deformation (RD) caused by errors in the pricking out process are irreversible and very difficult to detect in container-grown seedlings at the time of planting in the field. The objective of this study was to evaluate the effects of RD on leaf gas exchange, growth, biomass allocation and mineral nutrition of G. americana seedlings during the...

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: Phytosei...

This article summarizes the basic concepts of leaf water potential measurements and two available methods for measuring leaf water potential under field and laboratory conditions. Written by Christian Bartell, Haimanote K. Bayabil, Bruce Schaffer, Fitsum Tilahun, and Fikadu Getachew, and published by the UF/IFAS Department of Agricultural and Biolo...

Laurel wilt, caused by the fungus Raffaelea lauricola, is a lethal vascular disease that affects many members of the Lauraceae family, including avocado (Persea americana Mill.) trees. Previous studies have shown differences in laurel wilt susceptibility among genotypes, with cultivars of the West Indian (WI) race generally more susceptible to laur...

Salinity is one of the most common and critical environmental factors that limit plant growth and reduce crop yield. The aquifers, the primary sources of irrigation water, of south Florida are shallow and highly permeable, which makes agriculture vulnerable to projected sea level rise and saltwater intrusion. This study evaluated the growth respons...

Laurel wilt (LW) is a vascular disease caused by a fungal pathogen transmitted to avocado trees by several ambrosia beetle species and through root grafts among adjacent avocado trees. A critical part of preventing and controlling plant diseases is determining the causal agent so that the appropriate management practices can be implemented to eradi...

In subtropical regions, low-chill stone fruit (Prunus spp.) crops have experienced the negative impacts of flooding caused by hurricanes and tropical storms. These crops are considered very susceptible to oxygen-deficient soil conditions resulting from flooding. We investigated physiological and biochemical responses to flooding of six Prunus spp....

Laurel wilt (LW), caused by Raffaelea lauricola (RL), is a vascular fungal disease affecting species in the Lauraceae that has rapidly spread across the United States. This disease has caused significant tree losses in natural forests and Florida's commercial avocado orchards. RL spreads through ambrosia beetle vectors and root grafts. Early detect...

The success of watershed riparian forest restoration programs can be affected by the selection of plant species tolerant to flooding and soil types that occur along water courses. We evaluated physiological and growth responses of Cytharexyllum myrianthum seedlings to flooding in three different soil types representative of the Almada River Watersh...

Root hairs play an important role in phosphorus (P) nutrition of plants. To better understand the relationship between root hairs and P acquisition efficiency (PAE) in barley, experiments were conducted with the wild-type barley (cv. 'Pallas') and its root-hairless mutant (brb). A hydroponic split-root system was used to supply P as Ca 3 (PO 4) 2 (...

This is the Spanish translation of HS1358, Recommendations for the Detection and Mitigation of Laurel Wilt Disease in Avocado and Related Tree Species in the Home Landscape. Avocado trees are a popular choice for homeowners in Florida, with over 600,000 growing in Florida home landscapes. However, avocado trees as well as others in the Lauraceae fa...

This is the Spanish translation of Recommendations for Control and Mitigation of Laurel Wilt and Ambrosia Beetle Vectors in Commercial Avocado Groves in Florida (HS1360). Laurel wilt and the ambrosia beetle vectors that transmit this lethal disease have and will continue to affect avocado production in Florida. At least 50% of the commercial produc...

Water uptake from the soil via a vapor pathway was tested. Viburnum suspensum L. seedlings were divided into: (1) irrigated, (2) drought with vapor, and (3) drought without vapor treatments. Each plant was placed into a larger bucket containing deuterium labelled water as a vapor source (vapor treatment) or no water (drought and irrigation treatmen...

This article is part of a series on ET-based irrigation scheduling for agriculture. The rest of the series can be found at http://edis.ifas.ufl.edu/topic_series_ET-based_irrigation_scheduling_for_agriculture.

A two-year study was conducted to determine how soil texture affects calcium (Ca) absorption and partitioning in potted 'Hass' avocado trees. Trees were planted in 200 L pots in one of four soil types: clay (C), clay loam (CL), sandy loam (SL) or sand (S). Prior to planting, Ca content in each soil was in the normal range of availability, although...

Symptoms of laurel wilt, a vascular plant disease caused by the fungus Raffaelea lauricola, are similar to those of drought stress. We compared physiological responses of redbay and avocado trees infected with laurel wilt to responses of trees with drought stress. Trees were either inoculated with R. lauricola, subjected to drought stress, or irrig...

Optimizing plant physiological function is essential to maintaining crop yields under water scarcity and in developing more water-efficient production practices. However, the most common strategies in addressing water conservation in agricultural production have focused on water-efficient technologies aimed at managing water application or on impro...

Carpotroche brasiliensis is a native tree of the Brazilian Atlantic Forest with potential economic value for cultivation in agroforestry systems. We conducted an experiment to determine the photosynthetic and survival responses of young C. brasiliensis plants to electrochemical changes in flooded soils as an indication of their flood tolerance and...

AdditionAl index words: UV reflective plastic mulch, melon thrips, abundance, adult, larva Melon thrips (Thrips Palmi Karny (Thysanoptera: Thripidae) is a serious pest of vegetable crops and ornamental plants. This pest is difficult to control because it is not very sensitive to commonly used insecticides. We evaluated the impact of different plast...

Shallow aquifers significantly impact crop growth as saturated soil conditions may occur. Canals are widely constructed in such areas to mitigate groundwater saturation or flooding. We applied a simulation model to estimate the occurrence of root zone saturation [root zone saturation index (RZSI)] for agricultural crops and to identify factors that...

Practical use of PP system portable leaf gas exchange analyzer to measure the disease-induced stress in avocado trees.

Melon thrips, Thrips palmi Karny (Thysanoptera: Thripidae), is a serious pest of vegetable, ornamental, and fruit crops. As a potential component of an integrated pest management (IPM) program, different plastic mulches including white-on-black, black-on-white, black-on-black, two metalized ultraviolet (UV)-reflective mulches, and a no mulch contro...

Papaya (Carica papaya L.) is one of the main horticultural crops of many tropical and subtropical regions. The fruit is sold either as a fresh product or processed into drinks, jams, candies, dried and crystallized fruit, while the enzyme papain is used for medicinal purposes. Papaya fruits have high vitamins A and C contents, as well as are good s...

This study aimed at comparing the growth and physiological changes in Jatropha curcas L. (jatropha or physic nut) young plants fertilized or not with a commercial product based on a micronutrient delivery system (MDS), under different doses of NPK. Measurements of growth, chlorophyll content, and leaf gas exchange were performed in the greenhouse,...

The effects of plant age at the time of mowing on sunn hemp (Crotalaria juncea L.) tissue decomposition, nitrogen (N) release, and fiber content in Krome very gravelly loam were assessed. Combined leaf and stem tissue from 42-, 77- or 112-day-old sunn hemp plants was placed in mesh bags and buried below the soil surface in the field. Bags were remo...

The effects of irrigation water savings by partial root zone drying (PRD) irrigation, shading or mulching on physiology, growth, yield, and wine quality of 'Syrah' grapevine (Vitis vinifera L.) was investigated. The study was conducted in a vineyard at two different sites, each with a different soil type and vegetation index. Plants were subjected...

The mechanisms for tolerance of various abiotic stresses in plants are often considered to be similar, but there are also specific traits responsible for acclimation that differ according to the type and extent of stress. Water-deficit priming is the imposition of a period of moderate drought stress to induce tolerance to a subsequent stress. We hy...

In vitro efficacy of the essential oils extracted from eight plant species was tested at application rates of 100, 250, 500, 1000, or 2000 µl/l for controlling fruit rots. Results showed a 100% reduction of mycelium growth of Colletotrichum, Fusarium, Phytophthora, Botryosphaeria after applying thyme or savory oils at all concentrations tested. Min...

Water Scarcity and Sustainable Agriculture in Semiarid Environment: Tools, Strategies and Challenges for Woody Crops explores the complex relationship between water scarcity and climate change, agricultural water-use efficiency, crop-water stress management and modeling water scarcity in woody crops. Understanding these cause- and effect relationsh...

https://doi.org/10.1016/B978-0-12-813164-0.00019-3 Water Scarcity and Sustainable Agriculture in Semiarid Environment: Tools, Strategies and Challenges for Woody Crops explores the complex relationship between water scarcity and climate change, agricultural water-use efficiency, crop-water stress management and modeling water scarcity in woody cro...

Inhibitory effects of five different plant essential oils were assessed against papaya fruit decay caused by anthracnose. Essential oils were extracted from savory, thyme, cinnamon, mint, and lavender plants and chemical components of each oil were identified by GC-mass spectroscopy. The polymerase chain reaction (PCR) method using the internal tra...

Background and aimsRoot hair growth and development are important features of plant response to varying soil conditions and of nutrient and water uptake. Most current methods of characterizing root hairs in the field are unreliable or inefficient. We describe a method to quantify root hair area in digital images, such as those collected in situ by...

Additional index words. Carica papaya, regulated deficit irrigation, stress memory Abstract. Primed acclimation (PA) is a regulated deficit irrigation (RDI) strategy designed to improve or maintain yield under subsequent drought stress. A previous study showed photosynthetic increases in papaya in response to a PA treatment. The present study was u...

Papaya (Carica papaya L.) nutrient requirements can be supplied through fertigation. However, this application method can increase solute concentrations, thereby increasing salinity and raising the electrical conductivity (EC) of the substrate when the nutrients are applied at supra-optimal levels. This can profoundly affect plant photosynthetic ca...

We tested the inhibitory properties of five different plant extracts to extend avocado fruit shelf life against anthracnose (Colletotrichum gloeosporioides Penz.). Essential oils were extracted from mint, savory, thyme, cinnamon and lavender and then analysed by gas chromatography-mass spectrometry. Carvacrol(71.2%) and thymol (73.3%) were the main...

Laurel wilt kills American members of the Lauraceae plant family, including avocado (Persea americana). The disease threatens commercial production in the United States and other countries, and currently impacts the avocado industry in Florida. As laurel wilt spreads, the National Germplasm Repository for avocado in Miami (USDA-ARS) and commercial...

Jatropha curcas L. has been identified for biofuel production but it presents limited commercial yields due to limited branching and a lack of yield uniformity. The objective of this study was to evaluate the effects of single application of ethephon or a combination of 6-benzyladenine (BA) with gibberellic acid isomers A4 and A7 (GA4+7) on branch...

In many parts of the world papaya (Carica papaya L.) is prone to hypoxic stress due to soil flooding as a result of severe storms or hurricanes. Two experiments were conducted to test the effects of root zone hypoxia on physiology, recovery and survival of papaya and to determine if negative impacts of root hypoxia can be reduced by chemically enri...

Papaya (Carica papaya L.) production in Florida is concentrated in areas with a high water table that are prone to flooding resulting from storms or hurricanes. This can limit production because the crop is sensitive to flooding stress. Studies were conducted to examine physiological responses of papaya to flooding a portion of or the entire root s...

Priming is a strategy that potentiates a plant’s response to stress. Primed acclimation (PA) in crop irri-gation scheduling is the use of a temporary period of regulated deficit irrigation (RDI), imposing mild ormoderate deficits, to evoke a primed state, after which full evapotranspiration replacement is resumed.Although little has been reported r...

The light quality management promises to provide a new technological alternative to horticultural crops. Although plants utilize the full spectrum of visible light, some colors of light have more important applications than others. The objective of this study was to investigate the growth response and the yield of hot pepper (Capsicum annuum ‘Jalap...

This is a Spanish translation of the book "The Avocado, Botany, Production and Uses" edited by Bruce Schaffer, B. Nigel Wolstenholme and Anthony W. Whiley and published by CAB International Press in 2013.