Control Of Coffee Berry Disease Research Articles

The Potential of Fungi as Bio-Control Agents in Managing Colletotrichum Kahawae In Kenya

Colletotrichum kahawae is a causative fungal agent of Coffee Berry Disease (CBD) that negatively affects coffee production. Its control relies on use of resistant varieties and chemical control. Fungicides used in control of CBD are costly and pose a risk to environment and health. The study was aimed at assessing the possible antagonistic potential of fungal isolates against Colletotrichum kahawae in in vitro conditions. Five isolates were used; one isolate was collected from berries while the rest were collected from soil. Testing for antagonism against Colletorichum kahawae was done by co-culturing the isolates on Potato Dextrose Agar. The degree of antagonism was determined by measuring and comparing the radial growth of pathogen with the bio-agent against the control. Out of the five isolates tested against C. kahawae, three isolates Fusarium proliferetum, Penicillium and Fusarium ceraneasum significantly inhibited test pathogen growth at 60%, 55% and 45.45%, respectively. The other isolates, Fumigatus aspergillus and Chaetomium perithecia showed inhibition of growth at 40% and 18.18% respectively. It was concluded that there is potential of using fungi as bio control of the coffee berry disease.

The microflora of coffee surfaces and relationships to coffee berry disease

Data from previous trials that have been re-evaluated indicate that low levels of coffee berry disease on unsprayed coffee are associated with higher populations of microflora on coffee tissues. Samples were taken at different seasons and altitudes, and from coffee plots receiving different fungicide treatments for the control of coffee berry disease. Although largest populations occurred at the highest altitudes, the relative proportions of microflora components varied with altitude. Fungicides reduced populations of filamentous fungi on all tissues. Trees that had never received fungicide had low populations of Colletotrichum kahawae and had very low levels of coffee berry disease. The disease was also at a lower level on trees that had not been sprayed with fungicides for two seasons where microflora populations were highest. The likely effects of microflora components on coffee berry disease and their potential as biological control agents are discussed.

The performance of copper‐based bactericides in the control of bacterial blight of coffee and coffee berry disease in Kenya

Abstract In 2‐year field trials with three different copper formulations it was observed that the incidence of bacterial blight of coffee decreased in response to increasing amounts of copper in sprays. However, reduction of disease achieved by the sprays was not in proportion to the amount of copper in each formulation. Similar sprays of each of the three formulations achieved different levels of blight reduction in different sites. The sprays became less effective as bacterial blight infection pressure increased. The dual effect of these sprays on the control of coffee berry disease was also limited by the copper content in the sprays. The interaction of copper formulation, dosage and site factors in the control of bacterial blight, coffee berry disease and yield response are discussed.

Control of benomyl‐resistant strains of Colletotrichum coffeanum, the cause of coffee berry disease

Sprays containing difolatan, dithianon, chlorothalonil and cuprous oxide were tested for the control of coffee berry disease (CBD) in 1979 and 1980 at an estate in Kenya with abundant benomyl‐resistant strains of Colletotrichum coffeanum. In 1979 all fungicides gave good CBD control and increased yields of coffee. In 1980 only difolatan increased yield. Isolates of C. coffeanum capable of growing on agar with 8 μg/ml benomyl were detected throughout the 2 years of these trials.

Chemical Control of Coffee Berry Disease in Northern Tanzania—1978 Results

(1978). Chemical Control of Coffee Berry Disease in Northern Tanzania—1978 Results. East African Agricultural and Forestry Journal: Vol. 44, No. 2, pp. 140-145.

Control of Coffee Berry Disease in Northern Tanzania: 1976 Trials

(1977). Control of Coffee Berry Disease in Northern Tanzania: 1976 Trials. East African Agricultural and Forestry Journal: Vol. 42, No. 4, pp. 427-430.

Evaluation of fungicides for the control of coffee berry disease in Kenya

SUMMARYSome sixty fungicides were tested in the laboratory for ability to (a) depress sporulation of Colletotrichum coffeanum on the maturing bark of coffee shoots and (b) inhibit spore germination. On the basis of these tests over twenty products were selected for testing in the field during 1968‐70. Nine of these (50 % copper formulations, Ortho‐Difolatan, Daconil, Benlate, Topsin, Top‐sin M, Tecto 60, Delan and Du‐Ter) could be recommended for control of coffee berry disease (CBD) in Kenya.Field evaluation of fungicides is complicated by multiple flowering which creates a succession of overlapping crops, and by high variability in cropping potential which is often aggravated by normal pruning practices; in some circumstances other diseases and pests may also be a complicating factor. As a result, yield, which should be the most sensitive measure of CBD control, is at times even less satisfactory than disease estimates based on a small sample of the developing crop. Disease incidence in the ripe crop, which is easy to measure, is unfortunately not always well correlated with disease and crop loss earlier in the season. Consequently, critical assessment of fungicide performance requires estimates of both disease progress and crop loss.Consideration of fungicide performance indicates that physical characteristics, particularly persistence and capacity for redistribution, are especially important for effective control of CBD.

Some problems of evaluating fungicides for use on coffee in Kenya

SUMMARYAs part of a programme testing fungicides for control of coffee berry disease (CBD) promising materials were also tested in the field against leaf rust of coffee. In all, fourteen fungicides were tested, five of which have been recommended for control of CBD. Only Perenox (representative of 50% copper fungicides) and Du‐Ter (not highly effective against CBD and no longer recommended) gave good control of rust; Difolatan gave some control but Benlate and Daconil were virtually ineffective.Where only CBD is present there is generally a good relationship between disease control and yield, but in these experiments where leaf rust was also present, this relationship was seriously disturbed. The implications of this for testing fungicides for use on coffee in Kenya are discussed.

Overhead Application of Fungicide for the Control of Coffee Berry Disease

SUMMARYComparison of an overhead boom sprayer (Monica Mist) with a conventional air-assisted sprayer (Conomist) showed that the former gave relatively poor cover, but control of coffee berry disease (CBD) was equally good with both machines. It is suggested that the success of overhead spraying is dependent upon effective redistribution of fungicide within the tree canopy during rain.

Some factors influencing the performance of spray programmes for the control of coffee berry disease.

SUMMARYIn 1968 in a field trial at Kamundu, Kenya, early‐season (Jan.‐Mar.) sprays of copper, captafol and Tuzet failed to control coffee berry disease (CBD), in the late (main) crop of cultivars S.L.28 and S.L.34. Copper and captafol caused some delay in disease development but eventually infection reached over 50 % in all treatments and final yields of sprayed plots were below those from unsprayed plots.In a similar trial in 1969 at Yara on the cultivar French Mission a similar spray programme achieved significant benefits: copper and captafol kept the level of disease below 20% and gave improved yields compared with unsprayed plots. A continuation of the sprays until June increased yields still further.In a second trial in 1968 at Kiamara on the cultivar French Mission substantial quantities of early crop were present and disease in this was effectively controlled by early‐season sprays of captafol, although the late crop on the same trees became severely affected. Removal of this overlapping early crop in January caused only a limited delay in disease development in the late crop, despite the fact that with some treatments this stripping resulted in the removal of a large source of potential inoculum from the tree.The results are considered in relation to differences between seasons and fungicides and it is concluded that further evidence has been provided for the importance of the protective role of fungicides against CBD. It is considered that stripping of the early crop is never likely to be a necessary management practice.

Control of coffee berry disease*

SUMMARYField experiments comparing six spraying programmes and two fungicides for control of coffee berry disease were carried out at three sites during 1968. These established that protection of the crop by sprays applied throughout the long rains (February–July) gave the best control and increased yields threefold. Early season spray programmes, which reduced the sporulating capacity of the pathogen in coffee twigs, but which ceased before the end of the rainy season, gave no disease control in the late crop (harvested October‐December) and yields were less than in unsprayed controls. All programmes which gave protection at the onset of the rains gave some disease control in the early crop (harvested June‐August). Captafol (‘Ortho‐Difolatan’ 80 WP) was better than a 50% copper formulation (‘Perenox’).Conditions suitable for infection, as determined from meteorological records, occurred frequently during both rainy seasons. Estimates of sporulating capacity and data from spore trappings showed that although inoculum from the bark might initiate an epidemic, subsequent disease progress was more dependent upon spores derived from diseased berries; these accounted for most of the inoculum dispersed during the greater part of the season. Removal of the early crop, which was very small, had no detectable effect on disease in the late crop.Although losses were greatest with early season spray programmes, these did nevertheless delay the onset of the epidemic. However, the subsequent rate of disease increase was greatest and ‘scab’ lesion formation least in these treatments. ‘Scab’ lesions were most abundant in those treatments which caused least delay; in unsprayed coffee, it appeared that early exposure to infection resulted in ‘scab’ lesion formation which subsequently retarded the rate of disease progress. Tree height was positively correlated with disease incidence, but there was little effect of tree aspect. Crop density had a small effect on disease incidence within branches.

Early‐season sprays for the control of coffee berry disease*

SUMMARYBock (1963) showed that in the years 1956‐60 early season sprays achieved good control of coffee berry disease (CBD) in East Rift areas of Kenya. In recent years, however, this spray programme has given erratic and often very poor results. In field experiments in 1966 yields of main (late) crop were increased from 151 to 652 kg/ha by early season sprays but in 1967 practically no control of the disease was achieved. Of the fungicides examined captafol was superior to copper; ‘Tuzet’, the best antisporulant, gave the poorest control. Analysis of the data indicates that this large seasonal variation depends on the very different inter‐relationships between rainfall, cropping pattern and timing of sprays which obtained in the 2 years.The hypothesis that early‐season sprays achieve control of CBD mainly by reducing the sporulating capacity of the maturing bark is questioned. The view is put forward that the protectant action of these sprays has been underestimated.

Coffee Berry Disease: Epidemiology in Relation to Control

SummaryIn many instances measures developed for the control of coffee berry disease in East Africa have become less effective since 1961. Changes in the flowering and fruiting patterns of the coffee tree have recently become evident, ascribed in part to the onset of a wetter and cooler climatic cycle in 1961–62, and in part to the effect of the disease itself which, by removing crop, stimulates out-of-season flowering. Consequently, instead of a single main crop in which susceptible and highly infective ripe berries are present for a short time only, a series of over-lapping crops results in ripe berries being on the trees for most of the year. This has changed the disease epidemiology: formerly the main source of infection was conidia from the maturing wood, but now conidia from the berries are often predominant. This has greatly affected the efficiency of control measures, and means are suggested for restoring the previous situation.

The stimulating effect of some fungicides on Glomerella cingulata in relation to the control of coffee berry disease

SUMMARYThe non‐parasitic strain of Colletotrichum coffeanum Noack which colonizes the maturing wood of Coffea arabica produces its perfect stage (Glomerella cingulata) on the branches. Assessments of the relative abundance of this in relation to preceding rainfall have shown that for unsprayed branches, but rarely for sprayed ones, the correlation is negative and highly significant. Various fungicides stimulate G. cingulata greatly, and this stimulation persists for many months. One other saprophytic component of the micro–flora is similarly stimulated, but with two others all the fungicides used depress sporulation. It is suggested that when the main source of infection of coffee berries is the pathogenic conidia from the wood, the mechanism of long–term control by early–season sprays may lie partly in this stimulation of some fungal competitors of the pathogen.

The effect of fungicidal treatments on sporulating capacity in relation to the control of coffee berry disease

SUMMARYThe capacity of the maturing wood of the branches of Coffea arabica to produce conidia of Colletotrichum coffeanum Noack, the causal agent of coffee berry disease, is profoundly affected by fungicidal treatments. The effect differs according to the epidemiology of the disease. When the main source of inoculum is from the wood, the reduction in the sporulating capacity persists throughout the crop‐season, and good control of the disease results. When the main source of inoculum is from diseased berries, reinfection of the branches takes place, the sporulating capacity of sprayed branches rises above that of unsprayed ones, and there is indifferent or no control. Evidence from field trials suggests that the correct timing of early season spray schedules may be related to the part of the annual rhythm of sporulating capacity at which they are applied. As this rhythm is determined by rainfall, and varies from year to year and from place to place, the correct time for the start of a schedule should be predictable from meteorological data.

Screening Fungicides for Control of Coffee Berry Disease in Kenya

SummaryFourteen out of 43 fungicides were selected, after laboratory screening, for field trials against coffee berry disease. Each fungicide was compared with a commercial cuprous oxide formulation and an unsprayed control, by assessing conidial production of bearing coffee branches and by recording the percentage of healthy ripe berries picked. In assessments of fungicidal efficiency, healthy ripe berry counts gave more consistent results than those obtained by measuring conidial production. The results from berry counts indicate that in these experiments Ortho Difolatan (BSI ‘Captafol’) was equal, but not significantly superior, to the standard formulation used in estate spraying. The annual rhythm of conidial production seems to have changed over the past five years. The significance of this is discussed in relation to the control of coffee berry disease.

A comparison of fungicide spray volumes for the control of coffee berry disease

SUMMARYA continuation of previous trials in which three sprayers were used to apply 8.4 g. of Perenox in a range of spray volumes from 0.2 to 1.7 l. per tree confirmed that the volume of spray did not affect greatly the deposit retained on the branch surface. Branches were able to retain up to about 250 mg. Cu/m.2 and it is considered that a volume equivalent to 100 gal./acre would provide the greatest margin of safety to compensate for inaccuracies of application, while avoiding serious run‐off. Where coffee was well pruned, intensive copper spraying raised the annual yield by about 2 cwt. of clean coffee per acre. Copper spraying did not provide an adequate control of coffee berry disease and, under certain circumstances, increased incidence.

Spraying arabica coffee for the control of coffee berry disease

SUMMARYThree sprayers were used in each of three field trials to apply 8.4 g. of Perenox† per tree in a range of spray volumes from 0.2 to 1.7 1.Copper deposits and conidial inoculum potential were determined on sample branches. The critical sampling zone was between the fifth and eighth node proximal to the youngest node flowering in the current season.The low‐volume treatments were as effective as the highest (standard) volume in terms of copper deposit, reduction in inoculum potential and the number of diseased fruit, and in increasing the yield of coffee in the first year of the trials.

Control of Coffee Berry Disease in Kenya

A DISEASE of coffee berries, attributed to a form of Colletotrichum coffeanum Noack, was first described from West Rift areas of Kenya in 1922 1. It caused extensive losses and the abandonment of coffee cultivation on many estates, and although by 1939 selections of coffee which showed some degree of resistance had been made, direct attack with a considerable range of fungicides had led to little, if any, control of the disease. A detailed account of the disease and of investigations up to 1950 has been published2.