Supplemental fumigant placement improves root-knot and Fusarium wilt management for tomatoes produced on a raised bed, plasti-culture system in Florida’s Myakka fine sand.

Plant Disease ◽  
2021 ◽  
Author(s):  
Caroline E. Land ◽  
Gary E. Vallad ◽  
Johan Desaeger ◽  
Edzard van Santen ◽  
Joseph Noling ◽  
...  

Fresh-market tomatoes are produced on a raised-bed, plasti-culture system that relies heavily on soil applied, pre-plant fumigants for the management of soil borne pathogens, nematodes and weeds. Since the transition from methyl bromide to alternative fumigants, growers have experienced a resurgence of several soil borne pests and pathogens, including root-knot nematode caused by Meloidogyne spp. and Fusarium wilt caused by Fusarium oxysporum f.sp. lycopersici Race 3 (FOL). This resurgence is attributed to the inability of the alternative fumigants to effectively disperse through the soil in the same manner as methyl bromide. Two supplemental fumigation strategies, the application of chloropicrin below bed edges (supplemental PIC) and broadcast, deep shank applications of 1,3-dichloropropene (deep shank 1,3-D), were evaluated in conjunction with standard raised-bed applications of Pic-Clor 60, Pic-Clor 80, and Pic 100 covered with either a virtually impermeable film (VIF) or totally impermeable film (TIF). Large plot replicated studies were conducted in two separate commercial tomato fields with a history of production losses caused by root-knot nematode and Fusarium wilt. Deep shank 1,3-D applications significantly reduced the recovery of root-knot and total parasitic nematodes across field sites prior to the preparation of raised beds. Both supplemental PIC and deep shank 1,3-D reduced root-knot galling and Fusarium wilt incidence; although, the latter supplemental treatment statistically had the greatest impact. Neither the fumigant applied within raised beds nor plastic film had a significant effect on root-knot galling or Fusarium wilt. Although both supplemental fumigation strategies had a significant effect on pest and disease pressure, neither statistically improved tomato yields based on small sub-plot harvests. Controlled lab experiments confirmed the fungicidal activity of 1,3-dichloropropene against FOL, with LD75, LD90, LD95, and LD99 corresponding to estimated field application rates of 56.1, 93.5, 121.6, 184.7 L/ha, respectively. Results demonstrate how fumigant placement can improve pest and disease control activity with current fumigant alternatives to methyl bromide; and further support the broader pesticidal activity of some chemical fumigants.

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 480f-481
Author(s):  
C. Elizabeth Succop ◽  
Steven E. Newman

Fresh-market basil has become a viable greenhouse commodity in Colorado. Marketing pressures and profit advantages also encourage the production of certified organic produce. The research objectives were to determine the length of time basil plants were productive in the greenhouse and to compare the production of fresh-market basil grown with three root zone systems and two fertilizer treatments. The three systems were hydroponic rockwool slab culture, hydroponic perlite raised bed culture, and hydroponic peat/perlite/compost bag culture. The two types of hydroponic fertilizer treatments were a salt-based formulated nutrient solution and an organic solution consisting of fermented poultry compost, hydrolized fish emulsion, and soluble kelp. The plants were harvested once per week for fresh weight determination. The results from the two runs show greater productivity for the plants in the perlite system as well as the bag mix system when fertilized with the organic fertilizer compared to salt-based fertilizer. However, productivity of the plants in the rockwool system was greater with the salt-based treatment compared to the organic treatment.


2021 ◽  
Vol 11 (2) ◽  
Author(s):  
Olaf Kranse ◽  
Helen Beasley ◽  
Sally Adams ◽  
Andre Pires-daSilva ◽  
Christopher Bell ◽  
...  

Abstract Plant-parasitic nematodes are a continuing threat to food security, causing an estimated 100 billion USD in crop losses each year. The most problematic are the obligate sedentary endoparasites (primarily root knot nematodes and cyst nematodes). Progress in understanding their biology is held back by a lack of tools for functional genetics: forward genetics is largely restricted to studies of natural variation in populations and reverse genetics is entirely reliant on RNA interference. There is an expectation that the development of functional genetic tools would accelerate the progress of research on plant-parasitic nematodes, and hence the development of novel control solutions. Here, we develop some of the foundational biology required to deliver a functional genetic tool kit in plant-parasitic nematodes. We characterize the gonads of male Heterodera schachtii and Meloidogyne hapla in the context of spermatogenesis. We test and optimize various methods for the delivery, expression, and/or detection of exogenous nucleic acids in plant-parasitic nematodes. We demonstrate that delivery of macromolecules to cyst and root knot nematode male germlines is difficult, but possible. Similarly, we demonstrate the delivery of oligonucleotides to root knot nematode gametes. Finally, we develop a transient expression system in plant-parasitic nematodes by demonstrating the delivery and expression of exogenous mRNA encoding various reporter genes throughout the body of H. schachtii juveniles using lipofectamine-based transfection. We anticipate these developments to be independently useful, will expedite the development of genetic modification tools for plant-parasitic nematodes, and ultimately catalyze research on a group of nematodes that threaten global food security.


1970 ◽  
Vol 10 (45) ◽  
pp. 493 ◽  
Author(s):  
JW Meagher ◽  
PT Jenkins

In a field experiment with strawberries, pre-plant treatments with broad-spectrum fumigants methyl bromide-chloropicrin (450 kg/ha) or methyl isothiocyanate-dichloropropene (500 l/ha) (and 300 l/ha) controlled wilt caused by Verticillium dahliae Kleb and resulted in increased yields. Soil fumigation with the nematicide ethylene dibromidz (105 l/ha) also improved yields. It controlled the root-knot nematode (Meloidogyne hapla Chitwood), delayed the onset of wilt symptoms and reduced the severity of disease. This indicated a nematode-fungus interaction and is the first report of a Meloidogyne-Verticillium interaction in strawberry.


1987 ◽  
Vol 33 (5) ◽  
pp. 349-353 ◽  
Author(s):  
T. C. Paulitz ◽  
C. S. Park ◽  
R. Baker

Nonpathogenic isolates of Fusarium oxysporum were obtained from surface-disinfested, symptomless cucumber roots grown in two raw (nonautoclaved) soils. These isolates were screened for pathogenicity and biological control activity against Fusarium wilt of cucumber in raw soil infested with Fusarium oxysporum f. sp. cucumerinum (F.o.c.). The influence of three isolates effective in inducing suppressiveness and three ineffective isolates on disease incidence over time was tested. The effective isolates reduced the infection rate (R), based on linear regressions of data transformed to loge (1/1 – y). Effective isolate C5 was added to raw soil infested with various inoculum densities of F.o.c. In treatments without C5, the increase in inoculum densities of F.o.c. decreased the incubation period of wilt disease, but there was no significant difference in infection rate among the inoculum density treatments. Isolate C5 reduced the infection rate at all inoculum densities of F.o.c. Various inoculum densities of C5 were added to raw soils infested with 1000 cfu/g of F.o.c. In the first trial, infection rates were reduced only in the treatment with 10 000 cfu/g of C5; in the second trial, infection rates were reduced in treatments with 10 000 and 30 000 cfu/g of C5.


2007 ◽  
Vol 47 (5) ◽  
pp. 620 ◽  
Author(s):  
B. L. Blair ◽  
G. R. Stirling

Damage to sugarcane caused by root-knot nematode (Meloidogyne spp.) is well documented in infertile coarse-textured soils, but crop losses have never been assessed in the fine-textured soils on which more than 95% of Australia’s sugarcane is grown. The impact of nematodes in these more fertile soils was assessed by repeatedly applying nematicides (aldicarb and fenamiphos) to plant and ratoon crops in 16 fields, and measuring their effects on nematode populations, sugarcane growth and yield. In untreated plant crops, mid-season population densities of lesion nematode (Pratylenchus zeae), root-knot nematode (M. javanica), stunt nematode (Tylenchorhynchus annulatus), spiral nematode (Helicotylenchus dihystera) and stubby-root nematode (Paratrichodorus minor) averaged 1065, 214, 535, 217 and 103 nematodes/200 mL soil, respectively. Lower mean nematode population densities were recorded in the first ratoon, particularly for root-knot nematode. Nematicides reduced populations of lesion nematode by 66–99% in both plant and ratoon crops, but control of root-knot nematode was inconsistent, particularly in ratoons. Nematicide treatment had a greater impact on shoot and stalk length than on shoot and stalk number. The entire community of pest nematodes appeared to be contributing to lost productivity, but stalk length and final yield responses correlated most consistently with the number of lesion nematodes controlled. Fine roots in nematicide-treated plots were healthier and more numerous than in untreated plots, and this was indicative of the reduced impact of lesion nematode. Yield responses averaged 15.3% in plant crops and 11.6% in ratoons, indicating that nematodes are subtle but significant pests of sugarcane in fine-textured soils. On the basis of these results, plant-parasitic nematodes are conservatively estimated to cost the Australian sugar industry about AU$82 million/annum.


2012 ◽  
Vol 10 (3) ◽  
pp. 258-260 ◽  
Author(s):  
Mohar Singh ◽  
Z. Khan ◽  
Krishna Kumar ◽  
M. Dutta ◽  
Anju Pathania ◽  
...  

Fusarium wilt caused by Fusarium oxysporum, Schlecht. emend. Snyd. & Hans. f. sp. ciceri is prevalent in most chickpea-growing countries and is a major devastating disease. Host plant resistance is the most practical method of disease management. Indigenous chickpea germplasm reveals a heterogeneous genetic make-up and the response of resistance to wilt is an unexplored potential source for disease resistance. There are 70 indigenous germplasm lines selected on the basis of their agronomic performance and diverse areas of collections in the country. Of these, four accessions had a highly resistant score of 1 and six had a score of 3 using a 1–9 rating scale, indicating their level of resistance to Fusarium wilt (race 4). Other germplasm accessions of chickpea were found to be moderately resistant to highly susceptible disease reaction. Likewise, the same set of germplasm was also screened for Meloidogyne incognita (race 1) using pot culture under controlled condition. Only one accession was found to be resistant to this pest. These resistant gene sources can be utilised effectively for race-specific chickpea wilt and root-knot resistance breeding programmes.


Nematology ◽  
2021 ◽  
pp. 1-9
Author(s):  
Hung X. Bui ◽  
Johan A. Desaeger

Summary Cover crops can be a useful tool for managing plant-parasitic nematodes provided they are poor or non-hosts for the target nematode species. A glasshouse experiment was done to determine the host status of four common cover crops in Florida, sunn hemp, cowpea, sorghum sudangrass and sunflower, to pure populations of four common tropical root-knot nematode (RKN) species Meloidogyne javanica (Mj), M. incognita (Mi), M. enterolobii (Me) and M. arenaria (Ma). Tomato was included as a susceptible control. Eight weeks after nematode inoculation (WAI), tomato showed the highest root gall damage for all tested RKN species, with gall indices (GI) between 7 (Ma) and 8.5 (Me) and reproduction factor (RF) ranging from 20 (Ma) to 50 (Mj). No visible root galls were observed for any of the RKN species on sunn hemp and sorghum sudangrass at 8 WAI. However, Mj and Mi were able to reproduce slightly on sorghum sudangrass (RF = 0.02 and 0.79, respectively). Sunflower and cowpea were infected by all four tested RKN species, but host suitability varied. Sunflower root galling ranged from 1.1 (Me) to 4.5 (Mj) and RF = 3.2 (Me) to 28.7 (Mj), while cowpea root galling ranged from 0.6 (Mi) to 5.1 (Me) and RF = 0.8 (Mi) to 67.3 (Mj). Sunn hemp and, to a lesser extent, sorghum sudangrass were poor hosts to all four tested RKN species. Sunflower was a good host to all RKN species, but root gall damage and RF were lowest for Me. Cowpea was a good host to Mj, Me and Ma, but a poor host to Mi. Our results confirm and stress the importance of RKN species identification when selecting cover crops as an RKN management strategy.


1996 ◽  
Vol 21 (1) ◽  
pp. 186-187 ◽  
Author(s):  
David J. Schuster

Abstract Transplants were set 10 Mar, 18 inches apart on 8-inch-high beds of EauGallie fine sand covered with white polyethylene mulch. Each plot consisted of a single 15 ft row with rows on 5 ft centers. Treatments were replicated 4 times in a RCB design and were applied with a 2.5 gal, hand-held CO2-powered sprayer on 3, 10, 17, 24 Apr, 1, 8, 15, 22, 31 May, 6 and 12 June. The sprayer was operated at 60 psi and delivered 60 gpa for the first two applications, 90 gpa the next two applications, and 120 gpa for the remaining applications using a single nozzle fitted with a D-5 disk and #25 core. On 10 May and 19 June, the numbers of tomato pinworm leaf rolls were counted by two persons in a 2 min. whole plot search. On 10 May, the numbers of Liriomyza spp. leafmines were counted by two trained observers in a 1 minute whole plot search. Pinworm and leafminer damage counts of both persons were totalled. Fruit were harvested on 10 May, 1, and 15 June. The number and weight of undamaged fruit and the number and weight of fruit damaged by armyworm larvae and flower thrips (fruit with five or more oviposition dimples on the blossom end) were determined.


2019 ◽  
Vol 56 (1) ◽  
pp. 30-41 ◽  
Author(s):  
N. Thligene ◽  
G. N. Mezzapesa ◽  
D. Mondelli ◽  
A. Trani ◽  
P. Veronico ◽  
...  

SummaryPlant parasitic nematodes (PPN) are important pests of numerous agricultural crops especially vegetables, able to cause remarkable yield losses correlated to soil nematode population densities at sowing or transplant. The concern on environmental risks, stemming from the use of chemical pesticides acting as nematicides, compels to their replacement with more sustainable pest control strategies. To verify the effect of aqueous extracts of the agro-industry waste coffee silverskin (CS) and brewers’ spent grain (BSG) on the widespread root-knot nematode Meloidogyne incognita, and on the physiology of tomato plants, a pot experiment was carried out in a glasshouse at 25 ± 2 °C. The possible phytotoxicity of CS and BSG extracts was assessed on garden cress seeds. Tomato plants (landrace of Apulia Region) were transplanted in an artificial nematode infested soil with an initial population density of 3.17 eggs and juveniles/mL soil. CS and BSG were applied at rates of 50 and 100 % (1L/pot). Untreated and Fenamiphos EC 240 (nematicide) (0.01 μL a.i./mL soil) treated plants were used as controls. Reactive oxygen species (ROS) and chlorophyll content of tomato plants were estimated during the experiment. CS extract, at both doses, significantly reduced nematode population in comparison to the untreated control, although it was less effective than Fenamiphos. BSG extract did not reduce final nematode population compared to the control. Ten days after the first treatment, CS 100 %, BSG 50 % and BSG 100% elicited the highest ROS values, which considerably affected the growth of tomato plants in comparison to the untreated plants. The control of these pests is meeting with difficulties because of the current national and international regulations in force, which are limiting the use of synthetic nematicides. Therefore, CS extracts could assume economic relevance, as alternative products to be used in sustainable strategies for nematode management.


2021 ◽  
Vol 11 (23) ◽  
pp. 11286
Author(s):  
Marina Paula Secco ◽  
Débora Thaís Mesavilla ◽  
Márcio Felipe Floss ◽  
Nilo Cesar Consoli ◽  
Tiago Miranda ◽  
...  

The increasingly strong search for alternative materials to Portland cement has resulted in the development of alkali-activated cements (AAC) that are very effective at using industrial by-products as raw materials, which also contributes to the volume reduction in landfilled waste. Several studies targeting the development of AAC—based on wastes containing silicon and calcium—for chemical stabilization of soils have demonstrated their excellent performance in terms of durability and mechanical performance. However, most of these studies are confined to a laboratory characterization, ignoring the influence and viability of the in situ construction process and, also important, of the in situ curing conditions. The present work investigated the field application of an AAC based on carbide lime and glass wastes to stabilize fine sand acting as a superficial foundation. The assessment was supported on the unconfined compressive strength (UCS) and initial shear modulus (G0) of the developed material, and the field results were compared with those prepared in the laboratory, up to 120 days curing. In situ tests were also developed on the field layers (with diameters of 450 and 900 mm and thickness of 300 mm) after different curing times. To establish a reference, the mentioned precursors were either activated with a sodium hydroxide solution or hydrated with water (given the reactivity of the lime). The results showed that the AAC-based mixtures developed greater strength and stiffness at a faster rate than the water-based mixtures. Specimens cured under controlled laboratory conditions showed better results than the samples collected in the field. The inclusion of the stabilized layers clearly increased the load-bearing capacity of the natural soil, while the different diameters produced different failure mechanisms, similar to those found in Portland cement stabilization.


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