The use of narrow-angle cone nozzles to spray cocoa pods and other slender biological targets

Bateman, Roy

doi:10.1016/j.cropro.2004.02.014

Cited by 17 publications

(13 citation statements)

References 11 publications

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“…To that end, such studies require reliable estimates of cacao growth rates; for example, spray intervals could vary in relation to growth rates, with shorter intervals between spraying rounds when growth rate is at its maximum (around t m ), when pod surface area increases rapidly. Although it is difficult to relate ‘ideal’ deposits with biological effect, it is relatively easy to demonstrate that large amounts of pesticides are lost through run‐off from the crop into the soil (Bateman, ). Large droplets easily bounce‐off plant surfaces, whereas very small droplets can be displaced by the wind.…”

Section: Discussionmentioning

confidence: 99%

“…However, since a large variety of pod shapes exists, different models may be better suited for certain cacao varieties. According to Jessop et al (), their method was more appropriate for the cacao pod varieties grown in Ghana than the method used by Bateman () to estimate cacao pod surface areas for Costa Rican cacao varieties. While the calculation of pod volume provides an indication of the accuracy of pod surface area estimations, the method used by Jessop et al () appeared better suited to the cacao genotypes studied here.…”

Section: Discussionmentioning

confidence: 99%

“…Pod surface area was estimated using a slightly modified version of the model described by Bateman (). Our model was based on a hemisphere (pedicel end = 2π( D 1 /2) 2 ), a cylinder and cone 2π( D 1 + D 2 /4) L 1 and π( D 2 /2)√(( D 2 /2) 2 + L 2 2 ) (Fig.…”

Section: Methodsmentioning

confidence: 99%

“…However, it is a fact that fungicide spraying in cacao is often cost‐effective (Akrofi et al , ; Bateman et al , ; Gockowski et al , ) and for the time being, a necessity for ensuring efficient disease control. With the current interest in reducing pesticide dependency and its negative impacts on human and environmental health, it is surprising that only a few studies have focused on better timing of applications and improving dose transfer and spray deposition in cacao (Hidalgo et al , ; Bateman, ; Bateman et al , ; Jessop et al , ). Such an approach would reduce costs for farmers while, at the same time, reducing some of the negative externalities associated with fungicide spraying.…”

Section: Introductionmentioning

confidence: 99%

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Modelling cacao pod growth: implications for disease control

Hoopen

Deberdt

Mbenoun

et al. 2012

Annals of Applied Biology

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Cacao trees are affected by diseases that attack either their vegetative parts, their fruits or both. In cacao pod diseases, several factors are involved in disease susceptibility, such as the fruiting cycle, fruit size, age, position on the tree and cacao genotype. To gain a clearer understanding of how these characteristics influence cacao pod diseases, four models describing pod growth in several cacao genotypes were evaluated. Three models used to estimate pod volume or surface area were also compared. Observed pod growth was of a sigmoid form and fitted best to the Richards model, well to the Logistic and Beta growth models, and least to the Gompertz model. Pod volume and probably pod surface area were best estimated using a prolate spheroid model. Pod growth models can help improve pod disease management and thereby cacao production. They can help to predict yield, as well as provide information for the timing and frequency of control operations. Information on pod size, surface area and susceptibility will help to improve dose transfer and spray deposit studies intended to optimise control efficiency. (Résumé d'auteur

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Modelling cacao pod growth: implications for disease control

Hoopen

Deberdt

Mbenoun

et al. 2012

Annals of Applied Biology

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“…Many locally available manual sprayers are fitted with variable cone nozzles that produce an infinitely variable range of droplet sizes and flow rates, and farmers may have difficulty deciding which setting to use. One possible remedial approach is the development of a ‘cocoa nozzle’, which can be fitted inexpensively to manual sprayers, and would obviate the need for such local decision making, allowing farmers to concentrate on other aspects of better crop management (Bateman, 2004).…”

Section: Introductionmentioning

confidence: 99%

Application of chemical and biological agents for the management of frosty pod rot (Moniliophthora roreri) in Costa Rican cocoa (Theobroma cacao)

Bateman

Hidalgo

Garcia

et al. 2005

Annals of Applied Biology

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This article describes two field trials carried out at La Lola, Costa Rica, to assess control measures against frosty pod rot of cocoa (Theobroma cacao) caused by Moniliophthora (Crinipellis) roreri. In the first, factorial, trial the control agents were applied using motorised mistblowers (MMs) and hydraulic sprayers fitted with a narrow angle cone nozzle. There was an interaction between agents and application methods; together with previous application data for the most active fungicide (copper hydroxide), these trials indicate that best yields are achieved with sprays that maximise deposits on pods. We describe the droplet size spectra produced by a Stihl SR400 MM under a range of conditions because this has become the standard method of fungicide application in this series of trials at La Lola. The factor that had the largest effect on droplet size spectrum was the presence or the absence of a detachable baffle plate in front of the air-shear nozzle. In both trials described here, MMs were fitted with baffle plates, a formulation pump and restrictor transmitting 550 mL min 21 to deliver an estimated equivalent of 190 L ha 21 . Copper hydroxide as prophylactic applications at 1500 g a.i. ha 21 have, to date, shown the most consistent (but incomplete) improvement in healthy pod yield. Use of copper fungicides may be cost effective when farm-gate cocoa prices exceed approximately $1.25 kg 21 . In these trials, isolates of the hyperparasitic fungi Clonostachys byssicola and Trichoderma asperellum and two offpatent triazole fungicides (bitertanol and triadimenol) made no significant improvement to healthy yields. The systemic oxathiin fungicide flutolanil, at a dosage of 300 g a.i. ha 21 , appears to protect pods substantially at early stages but gives proportionately less control of M. roreri than copper at later stages of pod development.

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Hydraulic nozzles

2014

Pesticide Application Methods

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The use of narrow-angle cone nozzles to spray cocoa pods and other slender biological targets

Cited by 17 publications

References 11 publications

Modelling cacao pod growth: implications for disease control

Modelling cacao pod growth: implications for disease control

Application of chemical and biological agents for the management of frosty pod rot (Moniliophthora roreri) in Costa Rican cocoa (Theobroma cacao)

Hydraulic nozzles

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