The potential effects of climate change on cacao pests and diseases

Transcription

1 The potential effects of climate change on cacao pests and diseases Julie Flood (CABI) and Martin Gilmour (Mars) Indonesian International Cocoa Symposium (INCOSY) October 2017

2 Mars Company Overview Mars a family-owned business with more than a century of history making diverse products and offering services for people and the pets people love. With almost $35 billion in sales, we re headquartered in McLean, VA and operate in more than 80 countries. The Mars Five Principles Quality, Responsibility, Mutuality, Efficiency and Freedom inspire our more than 85,000 Associates to create value for all of our partners and deliver growth we are proud of every day. 2

3 The world is facing significant challenges like poverty, food insecurity and climate change. Businesses like ours have a significant role to play in tackling these challenges and shaping a positive, sustainable future. We will reduce our environmental impacts in line with what science says is necessary to keep the planet healthy. We will meaningfully improve the working lives of 1 million people in our value chain to enable them to thrive. We will direct our innovation pipeline and market our products in ways that help billions of people and their pets lead healthier, happier lives. 3

4 CABI in Brief Not-for-profit intergovernmental organisation established in 1910 by a UN treaty Provides scientific expertise and information about agriculture and the environment Expertise in: scientific publishing and international development Owned by 48 member countries 400 staff worldwide in 21 locations Annual turn-over 28m (2013) Compliant with requirements for Joint Management of strategic EC programmes, following successful 4-pillar audit in 2011

5 Regionalization of Major Cocoa Pests* Witches Broom Frosty pod P. megakarya Cocoa Swollen Shoot Virus Cocoa pod borer Vascular Streak Dieback 5

6 Region: Central, South America, Caribbean Frosty pod rot (FPR). Causal agent: Moniliophthora roreri Photographs: CABI 6

7 Region: South America and the Caribbean Witches broom. Causal agent: Moniliophthora perniciosa Photographs: CABI 7

8 Region: Central and West Africa Aggressive Black pod (BP). Causal agent: Phytophthora megakarya 8 Photographs: CABI

9 Region: West Africa Cocoa Swollen Shoot Virus

10 Region: South East & South Asia plus Melanesia Vascular-streak dieback (VSD) Causal agent: Ceratobasidium theobromae Photographs: D Guest & M Holderness

11 Region: South East Asia & PNG Cocoa pod borer (CPB) Causal agent: Conopomorpha cramerella Photographs: CABI, S Lambert & C Prior

12 Region: All cocoa producing regions Mirids/capsids. Causal agents: various sap sucking insects Photographs: CABI

13 Host, pest, and environment are interrelated Disease triangle (Gaumann, 1950) A dynamic process between a host, a pest and the environment (mutually influencing), resulting in level of disease observed Changes in the environment will impact the pest directly but also affects the host eg. host resistance Stressed plants are often more susceptible to attack Physical and biological component of environment eg natural enemies Complicated interactions which will influence the outcome of the amount of disease damage in any ecosystem Environment Host Pest

14 Climate change and cocoa production Various climatic models conducted to examine projected effects of climate change on cocoa production in West Africa Maximum dry season temperatures may become equal to, or more limiting, for cocoa as dry season water availability Perhaps necessary to reduce cocoa vulnerability to excessive dry season temperatures eg. adopt more shade Strong differentiation of climate vulnerability within the cocoa belt is predicted Difference in climate vulnerability could lead to future shifts in cocoa production within the region Partial compensation (losses and gains) for the cocoa industry; some winners some losers May be a risk of new deforestation (new areas more suitable for cocoa growing)

15 Climate change and insect pests Insects are cold-blooded so developmental rates of their life stages are strongly dependent on temperature (biggest influence) With every degree rise in global temperature, the insect life cycle will be shorter but increases impact insect populations in complex waysextension of geographical range increased over-wintering changes in population growth rate increased number of generations extension of development season changes in crop pest synchrony changes in interspecific interactions increased risks of invasions by migrant pests introduction of alternative hosts and over-wintering hosts More intense and more frequent rainfall is likely to have negative impact on insect populations

16 Climate Change and Cocoa Insect Pests Very little published effects of environmental factors on CPB Temperature and RH played a major part in the populations fluctuations of Sahlbergella singularis in Nigeria Second instar nymphs thrive more at very high humidity but desiccated at low humidity (linked to. decline in December) due to a drop in the RH. Rainfall not seen as important Problems with methods of measuring- higher temperatures / lower RH in the first half of the year associated with fewer mirids at hand-height (nymphs) but larger numbers adult males in pheromone traps Indirect effects - wetter conditions may need more insecticide sprays

17 Mealy bugs 6-10 generations/year on cocoa (Ghana) and field studies indicate presence throughout the year but more common in dry season (possible rainfall effect, or perhaps due to RH). Infestation in field increases when RH falls below 70% at noon (start of dry season) Significance of mealy bug movement in the canopy (linked with virus spread) Much work on other species eg Phenacoccus madeirensis (glasshouse pest). Higher temperatures affect development (degree days) so shortening the life cycle Laboratory studies suggest a complex interaction of temperature and the life cycle eg. egg laying, hatching, proportion of females to males etc. Effect of temperature on the biology of Phenacoccus madeirensis was stronger than that of the elevated CO 2 concentration Parasitism rates % increased with temperature too but not above 35 o C Need similar studies required on cocoa mealybugs

18 CSSV, drought and tree mortality Western Côte d Ivoire, 2015/16 dry season CSSV weakened trees dying under prolonged dry conditions?

19 Climate Change and Disease Spread Changing patterns of cocoa growing within countries /regions, some redistribution of cocoa diseases is inevitable Some as yet unknown and currently considered uneconomic pathogens may be more problematic Most likely factor in the extension of major cocoa diseases (outside their current regional distribution) is human mediated spread Raising awareness within the sector and with the public at large is needed to prevent accidental introductions Biosecurity planning will help to identify pathways of introduction, improve rapid detection introduced disease; more rapid detection is more likely to prevent disease establishment

20 Effects of Shade Many advantages to growing cocoa under shade (carbon storage, biodiversity) Role of shade in terms of disease suppression very complex Investigation in Costa Rica examined if FP was suppressed or encouraged in the farming systems there Suggested moderate and uniform shade is beneficial for FP suppression For other diseases of cocoa similar critical studies are needed for definite conclusions to be drawn. P megakayrya in Cameroon made worse by heavy shade P. megakayrya and for CSSV -shade trees could potentially act as alternative hosts so complicating the situation further as well as the potential interaction between these pathogens

21 General Conclusions and Recommendations Climate uncertainty is another threat for producers and whole cocoa industry Integrate biological data into existing climate data sets to help build more robust models and to help predict effects of changing weather patterns on cocoa pests (sensu lato) Models to be extended to all major cocoa producing regions Need more fundamental information on the effects of environmental factors on major pests and hosts. Address the major knowledge gaps. Funding of basic research to allow better modelling and promotion of existing (and novel) approaches to pest management

22 General Conclusions and Recommendations Need to raising awareness of likely scenarios to all stakeholders through the cocoa supply chain Optimised management strategies for all major pests under projected climatic change scenarios are needed Most likely factor in the global spread of major cocoa diseases remains human mediated spread Raising awareness of biosecurity planning is needed A more co-ordinated approach is needed to plan a global strategy for dealing with likely climatic changes over the short term (10-15 years) and further ahead (up to 30 years)

23 Summing up Climate uncertainty is projected to be a major challenge to cocoa production in the coming decades. Climate challenges combined with existing cacao pest challenges (as well as physiology, genetics, breeding, agronomy, cropping systems, etc.) Cocoa production needs to become more resilient to climate change Cocoa growers need advice and help to be more resourceful All in the cocoa sector need to be able to reap the rewards

24 Thank You!