Control of Disease Vectors using Fungi - Biological and Environmental Control of Disease Vectors - page 67

5

Control of Disease Vectors using Fungi

Jennifer C. Stevenson, 1* A.F. Harris 2 and B.G.J. Knols 3
1 London School of Hygiene & Tropical Medicine, London, UK; 2 The Mosquito
Research & Control Unit, Grand Cayman, Cayman Islands; 3 In2Care BV,
Wageningen, the Netherlands

5.1 Introduction

is minimized? How safe are these insecticides
for non-target organisms including humans?
Could they of er an alternative to conventional
chemical control?
The emergence and global spread of
chemical insecticide resistance has been best
documented in anopheline mosquitoes (Ranson
et al. , 2011), and as the majority of malaria
programmes depend on chemical vector control,
insecticide resistance could have a major
negative impact on the burden of malaria. This
threat recently prompted the World Health
Organization (WHO) to publish a document on
the management of insecticide resistance for
malaria control (WHO, 2012). While fungi have
been demonstrated to be ef ective against tsetse
fl ies (Maniania et al. , 2006), triatomine bugs
(Luz and Batagin, 2005), sandfl ies (Reithinger et
al. , 1997) and ticks (Kaaya, 2000; Kirkland et
al. , 2004), the greatest advancements have been
made in developing the technology for mosquito
control due to the urgent need for alternatives to
chemicals. This chapter aims fi rstly to introduce
and describe the pathogenesis of the two fungal
biopesticides that have received the most
attention and then address the above questions
in the context of malaria mosquito control.

When looking for alternatives to chemical
control of insects, fungi are an attractive option
over other biological control methods as they
can be used as contact insecticides and do not
need to be ingested by the target insect. Mass
production of spores, the infective stage, is
possible and formulating spores in oil to produce
ultra-low-volume sprays allows easy application.
Fungi are used to control agricultural pests and
there are several commercial fungal products
available for use both indoors and outdoors with
full registration dossiers and associated safety
profi les, making the transfer of technology from
agriculture to vector control a route worth
exploring.
There are, however, certain aspects that
need to be addressed before a fungal biopesticide
can be considered viable for vector control. What
is the best isolate to use? Is it best to select an
isolate with a fast rate of kill, or one with delayed
or sub-lethal ef ects that potentially delay
emergence of resistance? What is the best mode
of delivery of the biopesticide to ensure high
coverage? How can spore viability be promoted
such that after application frequent retreatment

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