This paper was presented at a workshop sponsored by
 ACRI, CAOBISCO & IOCCC

"CURRENT KNOWLEDGE AND PROGRAMS ON WITCHES' BROOM CONTROL"

Held in Miami, Florida on 19 & 20 February 1997

 
CHEMICAL & PHYTOSANITATION CONTROL OF WITCHES' BROOM FOR COCOA  
 
W. Martin Aitken
 
Almirante Centro de Estudos de Cacau
Barro Preto, Bahia, Brazil
 

PHYTOSANITATION

    The witches' broom bible, "DISEASE MANAGEMENT IN COCOA - Comparative epidemiology of Witches' Broom", published in 1993, and edited by Stephen Rudgard, Alan Maddison and Teklu Andebrhan is required reading for anybody interested in understanding witches' broom. It was the research output from the International Witches'Broom Project (IBWP) which ran for 7 years from 1985 and covered 6 different countries. An equally important article which appeared in the Cocoa Growers Bulletin of December 1981 writen by Harry Evans, here today, entitled "Witches' Broom Disease - a case study? gave a review of his experiences in Ecuador. His chilling description of how a large plantation under low/no shade conditions can rapidly be decimated as the owners try to prune and spray their way out of trouble is something we have seen in Bahia also.

    Phytosanitation or sanitation signifies the removal of diseased parts - shoots, flower cushions and pods, from the infected cocoa tree. The witches' broom disease cycle is amply described in the above two papers (Fig. 1). In essence the spores from the "crinipellis mushroom" or basidiocarp can only invade young tissue - shoots. flowers or pods. Swelling and a proliferation of new tissue is induced (hypertrophy and hyperplasy). The symptoms vary according to which type of tissue has been infected. Even after the infected part dies and dries up there is a 'maturing' or dormant (induction) period before that disease tissue will itself become infective and be able to produce basidiocarps of its own. This period varies but even with optimal conditions which would involve alternate periods of drying and wetting (Rocha & Wheeler l985) new basidiocarps will only appear after 4 to 5 months from initial infection with a range between 3 and 8 months. Herein lies the theoretical opportunity. Since the disease is not translocated downwards within the tree. the removal of the diseased tissue coupled with its destruction. such as burning. should eliminate the disease totally. Total eradication in this manner was attempted when the disease first appeared in Bahia. Nearly 140 hectares of cocoa and forest were totally destroyed but even with intensive scouting it was later found to have escaped the original area and with the discovery of further outbreaks eradication was superseded by a program of sanitation. Since sanitation is labor intensive and thus an expensive task most of the research in the countries where witches' broom is present has revolved around finding the optimal sanitation program for a specific set of climate conditions. The results of the IWBP recommended different times of primers and secondary removals (Table 1). The removals were often related to the timing of the dry season such that there would be a maximum period of non-basidiocarp producing tissues on the trees.

Table 1: Regional Guideline for the timing of primary (P) and secondary (S) removals of diseased witches' broom materials from cocoa .

Country/Month        Jan   Feb   Mar   Apr   May    Jun     Jul    Aug   Sep   Oct   Nov   Dec 
Brazil - AM1               P P   S S
Brazil - BA2     P P           P P  
Ecuador3             P P P   S  
Colombia   P P       S          
Venezuela4     P                  
Trinidad     P           S      
Grenada     P                  
1 Amazon region;  2 Bahia;  3 Coastal region;  4 Tachira State
(Adapted from Disease Management in Cocoa; Rudgard, Maddison & Andebrhan (1993) p. 209)


    In Bahia the absence of a defined dry period makes both the Oct/Nov and Mar/Apr prunings of equal importance. The most intense flush is usually in September followed by 2 – 3 less intense flushes occurring between December and March (Rocha et al 1993). The timing of the main flush may be offset on either side depending on the rainfall pattern of a specific year as will the level of its intensity. Winters (Jun/Sep) are cooler and wetter, though not necessarily with the highest rainfall. It is in June and July that we typically see the highest number of basidiocarps. In July 1995 at Almirante we were recording almost 180 basidiocarps per broom which had fallen to 60 by September. In the same year in Camacã, 80 kms to the south, at CEPLAC's main epidemiology site they recorded 431 basidiocarps per broom in July which was zero by September (Luz unpublished). However, in 1996 which was uncommonly dry during the winter months, we recorded 6 basidiocarps per broom in July and in the months following through February 1997 the range has been between 4 and 6 per broom per month. Such a difference would suggest that pod losses would be significantly lower in 1996 than in 1995. In absolute numbers that has been true but as regards pod disease index this was not the case. In 1995 we were losing 60-70% of all pods in Sep/Oct but in 1996 were still losing 50%. The very low pod load was due to the long drought and very poor setting that we experienced for the Bahia main, crop. In Bahia sanitation by itself is no guarantee that the pods harvested during the main cropping season (Sep/Nov) will be sufficiently free of the disease to make the activity economic. The evidence from the last two years would suggest that the early, crop (that which is harvested between April and July but which was susceptible to witches' broom between November and February) escapes infection. But will that be the case for all years? The last two years in Bahia have been very strange. In late 1994 early 1995 there was a massive rain failure which lead to an extremely low Temporão crop (May/Sap). In 1996 the autum/winter rains which usually never fail were absent and led to a very low Main crop which we are experiencing at this moment. That drought finally broke in November 1996. The massive flushing which followed became infected with witches' broom, and is now being accompanied by higher than usual pod losses of young cheerless. Yet this Increase in infection was not accompanied by any significant increase in basidiocarp production in the months when those pods would have been susceptible. It would appear that as long as the background inoculum pressure is extensive it does not need large numbers of basidiocarps to be recorded for there to be a high disease index.

    It is easy to use the word sanitation, but in a real life situation it is very difficult for laborers to remove all the infection points. Not only the literature (Evans 1981) but also personal experience showed that even when all visible witches' broom had been removed by a contractor from a relatively small tree there were still 134 infection points which had been missed. Since it can take up to 90 minutes to remove all the infected brooms and flower cushions from big tall intertwined trees any phytosanitation program has to be predicated with a substantial lowering of the canopy and removal of excessive internal branches. This will inevitably reduce yield in the early stages of a sanitation program. The obvious recommendation is that this be done before witches' broom actually arrives and that the search for short stature tree should be incorporated into breeding programs. Cocoa has a very irregular architecture and after a severe sanitation the trees can appear like fishing poles with a tufts of leaves at the end of spinal! branches. Laborers find it difficult to visualize what a badly infected tree should look lithe alter pruning. Subsequent excessive pruning of the axillary shoots/chupons, which w ill inevitably develop on the upper surface of the branches will often lead to die back; of the canopy. Sun is able to penetrate to the ground, weed cover increases. trees become debilitated. some die. open spaces appear in the plantation, the gaps increase in size and before long the field represents a Swiss cheese. Worse is that if these gaps are left for two to three years it will be increasing difficult to reestablish cocoa on those fields. Some genotypes and their hybrids are so badly susceptible lo witches' broom that if present it is probably best to eradicate. substitute or rehabilitate with something more tolerant. Any UF (United Fruit) progeny seem to have so many cushion brooms that the cost of sanitation is just too prohibitive and time consuming to be worthwhile.

    The actual process of pruning is usually done With small pruning knifes stuck on the end of long poles which also double as harvesting poles. While not common, more farmers are moving to have small chain saws to lop off the larger branches and cut up the thicker debris instead of using the ubiquitous all purpose machete and sometimes an ax. A chain saw speeds up the process considerably. Chain saws are readily available in Bah and cost between R$800 and R$1K. However, they are often turned over to untrained workers and the resulting high costs of maintenance offsets the initial improvement in productivity. When a field is pruned for the first time and there is a lot of infected debris on the ground there is a natural desire to remove and burn. Basidiocarps can still develop from the dry branch and leaf litter left on the ground and can be a site of new infections. More important for reinfections are the dry brooms and pods left hanging in the canopies. In practice, the time taken to remove all the infected debris. the risk of fires spreading into the cocoa from the burning heaps is such that it is more cost effective to leave the material under the cocoa with the very important proviso of chopping the branches into small pieces such that as much as possible is in direct contact with the soil surface. This is to facilitate the invasion by secondary organisms to speed up the rate of decay. Crinipellis is susceptible to many soil borne bacteria and fungi e.g. Trichoderma spp. Covering the cut litter with leaves is also recommended, since this will reduce sporulation, but is really only practical if available in the immediate vicinity. Heaping the cut litter and covering it up with leaves is not recommended. Pneumatic shears are being used by one large farmer in Bahia with success. Time consumption for pruning a tree can be reduced by a third and is certainly easier on the worker. This equipment works best from the power take-off of a tractor. Using a tractor in a cocoa plantation predisposes that there is a good network of feeder roads in the plantation. Other models exist which can be dragged into the cocoa but the hilly terrain of much of the Bahia cocoa region will not facilitate the use of such equipment on a large scale and the initial cost of R$14,000 for a reasonably sized unit is what most farmers can afford today.


CHEMICAL

    Since phytosanitation on its own is not a recipe for success much effort has been expended in trying to find chemicals which can assist in improving its efficiency. The literature is full of articles (Laker & Rudgard 1989, Cifuentes et al 1981, Mayorga & Aranzazu. 1981,  Medeiros 1977) describing tests which often show some positive activity particularly when they are in vitro experiments but that when they are taken to the field their efficiency is dubious, or unproven especially when their cost is added to the overall bill. Most fungicides are either of the protective, systemic or plant regulator type. The protective fungicides, of' which copper is the most common. attempts to provide a thin film of the chemical on the surface of clue pods which will prevent the germination of the basidiospore when it alights on the young pod or growing point. The systemic fungicides are compounds which destroy/eliminate the invading mycelium or inhibit broom formation. The plant regulators are similar to the systemic fungicides but that they are naturally occurring and are used to counterbalance the hormone response caused by the fungus. They can also be compounds not normally present in the tree which activate the plant s natural defense mechanisms, called Systemic Activated Resistance (SAR). A table is included with the names of some of these products (Table 2) mentioned in the literature. This list makes no claim to be exhaustive but illustrates that many compounds hare already been tried.

Table 2: Chemicals already tested for efficacy against Witches' Broom

Compound Trade Name Compound Trade Name
biloxazo Baycor cuprous oxide Coppr Sandoz
triademifon Bayleton cuprous oxide Gaia
oxicarboxin Plantvax copper hydroxide Garant
carboxin Vitavax copper oxychloride Funguran
piricarbolid Sicarol copper oxychloride Recop
agricultural oil Sun Oil #9 salicylic acid Sigma
clove oil Clos 96 EDTA Sigma
fosetyl - al Aliette sulfur Thiovit
fenpropimorph BAS 421 00F Piper aduncum Pepper Oil
benomyl Benlate captofol Otho Difolatan
6 benzyl amino purine (BAP) Sigma captofol+copper+zinc Otho Zincofol
tridemorph Calixin tin Brestan
cyclohexamide Cyclohexamide (BDH) quaternary ammonia Fegatex
carbendazim Derosol quaternary ammonia Fungraqiuat
diphenoconazole Score fluquinconazole Palisade
tebuconazole Folicur (CE 200, 200) hexaconazole Anvil
propiconazole Tilt cyproconazole Alto 100
triazole E 969 (ICI) isoprothiolane Fuji-one
indole 3-acetic acid (IAA) Sigma flutolanil Moncut
l-tyrosine L-tyrosine (BDH) oxytetracycline Terramycin tree injection
  Sportack   Systhane
  RH 7592   Parasol
  Busan   humus
  Guri   Lactating cow urine


    Since the advent of witches' broom in Bahia CEPLAC researchers have tested a wide array of new and old products (Almeida 1996, Oliveira 1996) With similar results. Farmers. life housewives who wish to see all their kitchen flies dead. typical!! demand products which are 100% effective. This is inevitably impossible in a tropical agricultural environment. Due to the desire to find something or anything which would control witches' broom even strange and exotic compounds hare been used such as lactating cow urine (Almeida 1996). or "Effective Microorganisms" (EM) from the Okada Foundation, a concoction of yeasts, actinomycetes, lactic acid bacteria and photosynthesizing bacteria (Silva et al. 1996), The latter showed no fungistatic activity although it did have some biofertilizer effect, Some companies unscrupulously advertised and sold products of the quarternary ammonia type which were only later show n to have no value whatsoever although many gullible farmers were persuaded to try them (Oliveira 1996). To date the only recommended product in Bahia is cuprous oxide (Copper Sandoz) applied as a protestant to the young developing pods. Applied at monthly intervals for 5 to 6 months from March onwards pod losses have been reduced at the critical Sep/Oct period to between 10-15~. Another product which has shown promising field results (Oliveira.1996) is the systemic triazole tebuconazole (Folicur by Bayer). Both these results have also been confirmed by Machado & Aitken (1996) In both cases the good results were only achieved if thorough satiation was part of the total lntegrated Disease Management. Another important trial has been that by Asha Ram (CEPLAC) with Nestlé sponsorship to determine if the labor component of the cost could be lowered by reducing the number of sprayings although maintaining the total amount of copper used. His trial began ill 1996 and due to the atypical weather patterns requires further tests to validate the initial findings (Table 3). However, there would appear to be some scope in reducing the number of spraying cycles. The two sprayings with 9g of copper (18g commercial product) per tree looks very promising. Another study in progress at CEPLAC by Antonio Zozimo (PhD thesis) measuring the residual effect and retention capability of copper on pods suggests that the normal recommended dosage of 3g of copper per tree per spraying could be reduced to l.5g, a potential additional cost saving (personal communication). The use of clove oil (Clos96 by Thermo Trilogy) and pepper oil (laboratory extract from Piper aduncum?, by CEPLAC Belem) have been tried by Machado (Almirante) and Bastos (CEPLAC) respectively. Both show good control of Crinipellis in vitro and also some promise in the field. Further trials are planned for 1997 where a full spraying season can be evaluated. One of the new SAR products from Ciba-Geigy, "Plant Activator - CGA 245704, was also tested in late 1996 by Castro (Novartis - personal communication) on a farm in the Buerarema district. Once again the late start and incomplete spraying cycle could explain the promising results for broom suppression but little effect on pod infection. The results were extremely preliminary and further work is scheduled in 1997 at Almirante.

    Work by the CEPLAC researchers both in Belem and Itabuna have indicated that the use ot biological agents such as Trichoderma viridii in Belem and T. polysporium in Itabuna can reduce the basidiocarp production on ground litter by 70 - 80%. Spraying a suspension of these these fungi into the canopy also reduces basidiocarps but only to around 40%. Neither of these products is available commercially. Robert Lumsden (USDA-Beltsville) has just started a cooperative program with Almirante to evaluate the products Soilgard and Aspire (Thermo Trilogy) which are commercial products of 2 antagonistic fungi, Gliocadium virens and Candida oleophila respectively. However, the subject of biological agents will be more fully explored by Dr. Harry Evans later this morning.

    Irrespective of their actual costs the application of fungicides runs into a major practical barrier which is the lack of reliable, cheap applicators. The traditional mode of application is the use of motorized (3-3.5hp) backpack atomizer sprayers. They were designed for owner worker farmers with maybe 5 hectares of a particular crop. A wide range of models exist. In Brazil the common brands are Jacto, Hatsuta, and Guarani. Current price per unit is about R$1,3OO although discounts are available. The tank capacity is 20 liters and spraying 400 ml per tree a good operator can do 800 trees per day - in theory. In practice like cars, the best model is a new model, for rapidly mistreatment, poor daily maintenance etc., leads to breakdowns, prolonged downtimes, expensive repairs and total frustration. Only the larger farmers have the luxury of their own workshop. The sprayers have to be repaired in some local town. The journey from the shop back to the farm is usually on bumpy, roads and by the time they arrive back they need further repair or readjustment. To spray against Black Pod disease (Phytophora palmivora) it is unlikely that one has to spray the whole farm - it will tend to be those low-lying, heavily shaded areas which usually do not represent more than 20-30% of one's cocoa (in the Camaroons or parts of Papua New Guinea it may be closer to 80%!!!). However, for witches' broom the recommendation is for the whole farm to be sprayed monthly 3-6 times (Mar-Jul) which is a period when there is a lot of other activity going on e.g., brushing/ chupon removal/ harvesting. It is not surprising that a farmer with lOO ha of cocoa (medium size in Brazil) finds it difficult to complete his first round, never completes his second and subsequent rounds are small percentages of good intentions. To do the laborer justice, training is often minimal, the machine when full loaded weighs 32-38 kg, the decibel level high for 8 hours of work, and safety equipment rarely provided (ear protectors would be good start). Hence the trials by Asha Ram with his reduced spraying cycle program could hold a lot of potential if they can be validated over a wide range of conditions and tree types.

    In an attempt to decrease maintenance costs some farmer, use the high pressure back-pack sprayer which consisting of pumping up (manual or compressor) the pressure in the spray cylinder to 60 psi which then slowly goes down during the spraying cycle to to 30-4O psi. The machines are very robust and the noise minimal. Coverage starts well in the beginning but has diminished considerably by the end. Three farmers are using the tractor mounted Berthoud canon sprayer which has been adapted from the model used for bananas. It works well but calibration is difficult and droplet size very variable. Once again it predisposes the availability of feeder roads in the farm, that the cocoa has been reduced in height and that the shade trees have been trunk trimmed. The ideal situation would be a systemic compound which could be applied by tree injection similar to work by David Guest who with the SAR type compound potassium phosphonate (PP) controlled black pod for periods of 12 months in Papua New Guinea (Guest 1996). Figueira (Almirante) experimented with tree injections of PP for black pod and witches' broom control but while good results were found for black pod, PP had no activity for witches' broom. Tree injections with 2 triazoles also had no effect. CEPLAC researchers are working he conjunction with some of the machine manufacturers to make cheap, worker friendly and efficient equipment (Lavinscky personal communication) but there is a long way to go before there is something practical and commercially available.

    Aerial spraying is usually considered an impossibility due to fact that the many shade trees would presumably take out most of the fungicide applied. However in 1977, a year when black pod disease had been particularly severe in Bahia. CEPLAC compared cuprous oxide spraying by the motorized atomizers and helicopter equipped with Micronair sprayers over extensive areas. The results (Ram & Medeiros 1977) suggested that control was comparable and the cost was lower for the helicopter spraying. The target was the same although hi the case of black pod the pods are larger at the time when protective sprays are required. For witches' broom control it would require that all the area to be sprayed (by necessity large and encompassing a plumber of properties) would have had to have been pruned prior to the spray cycle. Aerial spraying against black; pod did not go further because hi the individualistic psychology of the farmer. CEPLAC should be responsible for the activity and take on the whole cost to which CEPLAC was unable to commit.


COSTS

    Phytosanitation and chemical control costs vary from farm to farm according lo the severity of the witches' broom infection. Labor can be piecework; contract workers or workers resident on the farm with a fixed monthly wage. Distance from a village will influence availability of day workers and the transport of the various inputs. If the farm is located near to a main road fertilizer for example could be purchased on a closed truck basis and delivered direct from the factory. As distances lengthen and road conditions worsen the fertilizer would have to offloaded and secondary transport used which will add at least a further 10% on to the purchase price. Table 3 shows minimum costs for the various activities involved. Weed brushing is included as is fertilizer application because it is an integral part of the package. Benefit rights have not been computed in this simplified structure. In Bahia the working week for a labors, is 44 hours with paid Sundays. There is a Christmas obligatory bonus (13th month) of one months pay. Holidays of 4 weeks per year are paid at the rate of 1.333 times average monthly pay and a deferred benefit paid at the rate of 8% of monthly pay. Unfair dismissals also carry penalty charges such that overall labor costs can represent almost an 80% increase over the monthly wage of the agricultural worker. Social security charges are levied on the farm production. It is not surprising that farmers are now looking for ways to reduce the hidden labor charges by either using short term contracts or sharecropping systems. If one just looks at the witches' broom component (removals and 6x spray cycle) and ignoring any investment in canopy reduction. the cost would represent at today's farm gate prices the equivalent of 450kg/ ha. for a farm with a Level 3 severity of infestation. once again ignoring machine depreciation and maintenance. With the poor Heather of the last two years not many farms have been yielding 450kg/ ha. let alone an extra 450kg. In practice few farmers ever complete the full spray cycle and thus never spend the money.

Table 3: Costs for Integrated Control of Witches' Broom (simplified)

    Level 1 Level 2 Level 3
LABOR   164 188 388
 - brushing 7dx2 64 64 64
 - WB removal 1dx2 16 (2d) 40 (5d) 240 (30d)
 - fungicide application 2dx6 60 60 60
 - fertilizer application 6dx1 24 24 24
SUPPLIES   307 307 307
 - fertilizer NPK x1 97 97 97
 - fungicides x6 150 150 150
 - fuel (sprayers) x6 60 60 60
TOTAL (R$)   460 495 695
@/R$17   27 29 41
kg equivalent   407 437 613


DISCUSSION

    The following commentary relates to the effect of witches' broom on cocoa in Bahia. This is deliberate since this is the area where I live and work. The difficulty of successfully growing cocoa in the Brazilian state of Bahia, which reached an estimated maximum of 650K hectares under cocoa in the late 1980's, can be summarized in two words Crinipellis perniciosa or witches' broom disease. Since its official advent in 1989, the disease has extended its spread to almost 90% of the region although its intensity varies considerably usually in relation to when the disease actually arrived in a specific area. There are still some areas where incidence is minimal but most observers believe that it is just a matter of time with little hope of "disease-escape" conditions.

    The Bahia cocoa region which once produced over 400K tonnes of cocoa has one of the largest single areas of contiguous cocoa in the world but with its predominance of susceptible amelonado genotypes the disease has been dismantling the traditional terms of value within the region. True the poor weather patterns of the last 4 years with reduced rainfall and strange distribution have not helped and in the short term have actually been more important. The Bahia cocoa crop for 1996/97 is unlikely to be much over 170K tonnes. The economic stabilization program known as the 'Real Plan which has wrought a miraculous turnaround for man)' Brazilian companies. particularly in the food sector, has resulted h, a doubling of real costs to the cocoa farmer. Previously the salaries paid by farmers were insidiously subsidied by inflation which in June 1994 was a staggering 49% per month. Weekly wages paid at the beginning of a month were hopelessly different in value to the wages paid at the end of the month. Inflation is now less than 1% per month with an expectation for 1997 of an annual rate of 9%. A typical laborer's wage used to be US$60/month and is now R$113/month (US$107 approx.) excluding benefits. This may still be miserably low, depending on whether one is receiving or paying, but at least its value has for the last two years been relatively constant. Salaries coupled with a general increase in prices of other farm inputs like fungicides, herbicides and services e.g., sprayer repairs, have eroded the terms of trade which have not been ameliorated by any increase in cocoa prices. Farm gate prices for cocoa have improved over their 1994 lows of US$800/tonne but are still only US$1,090/tonne (7/03/97). While the cocoa columnists of Salvador suggest that the world price should really be US$2K and happily predict that based on studies from the major trading companies prices will be US$3,000 he two to three years, the farmer waits in expectation, putting off until tomorrow what should be done today.

    To be a cocoa farmer was he the past an envious activity. The general perception was one of easy riches and the simple act of owning a cocoa farm was a sure sign of wealth. In times of high inflation one of the seemingly best hedges was to buy property, often another farm. Much money was made in the time of price booms but often little was spent on the farm. Rather than improve one's cocoa it was better to invest in more cocoa land. The truth today is very different although old perceptions die hard and sympathy is in short supply. In the past cocoa farms typically were sold based on a rule of thumb of five times earnings. A hectare of cocoa in 1979 could be sold assuming a good production of 5O arrobas/ha (750kg/ha) at close to US$10K. In 1983 a friend with 180 ha of cocoa producing just over 9,000 arrobas refused US$1.5M (US$8,333/ha). Now he would be lucky to receive R$800/ha for his land. Although he lived on his farm (a rarity in Bahia) and worked his farm diligently, productivity fell >50K trees died from drought. His production in 1995 was 604 arrobas. In 1996 he borrowed R$46K under the government's cocoa recovery program and applied all of it on phytosanitation, fertilizer and fungicides. The value of his crop in 1996 was little over R$15K from 805 arrobas. The location of the farm - near Camacã is in the heart of the major witches' broom outbreak. Whether its introduction from Rondonia in the Western Amazon was accidental or as many suppose intentional, the result has been the same - large swathes of cocoa with masses of brown dead brooms in the canopies with undergrowth a meter tall, a sure sign that that owner has abandoned the fight. The Bahia cocoa region is seriously undercapitalized and worsened by a lot of debt held by banks and shippers which is almost unrecoverable.

    With the title of my topic "Chemical & Phytosanitation Control of Witches' Broom" you may be asking what my comments above have to do with the subject. Unfortunately it has everything to do with the subject because it's all about money and being able to pay for the agronomic recommendations be they new planting initiatives or phytosanitation/ chemical and having a confident chance that it will be profitable, sustainable and in the case of loans repayable. The intensity of the witches' broom threat for each country or region depends on the prevailing socio-economic conditions, land tenure and even government exchange policy. In Ecuador the government favors an export policy. The labor cost there in dollar terms is half that of Bahia, not because the workers live worse, they probably live as badly as each other but in Ecuador the export income buys more.

    Phytosanitation with chemical spraying works but there has to be commitment and involvement from the farmers and workers alike. To be successful both have to come together. It can be done. In Bahia there will be change. Many farms will change hands. Today more people can have access to the land, something difficult a few years ago. Cocoa is still the best alternative crop for southern Bahia.

Photographs courtesy of Dr. Hank Purdy.

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