Integrated control of thrips in vegetables in eastern Africa - icipe

Integrated control of thrips in vegetables in eastern Africa
Annual Technical Report
P. O. Box 30772-00100 Nairobi, Kenya
Phone: +254 (20) 8632000; Fax: +254 (20) 8632001/2
Email: icipe@icipe.org Website: www.icipe.org
Feb 2009
Project Leader: Dr. Subramanian Sevgan (ssubramania@icipe.org)
Plant Health Division
Reporting Period: January 2008 – December 2008.

1. Name of IARC
The International Centre of Insect Physiology and Ecology (icipe)
2. Project Title
Integrated Control of Thrips in Vegetables in Eastern Africa
3. GTZ Project Number and Contract Number
Project number: 07.7860.5-001.00
Contract number: 81099947
4. Reporting Period
January 2008 - January 2009
5. Project Coordinator and Project Scientists
International Centre of Insect Physiology and Ecology (icipe)
Subramanian Sevgan, Entomologist, Principal investigator
Postal address:
ICIPE, P.O. Box 30772-00100
Nairobi, Kenya
Tel: +254 20 8632000
Fax: +254 20 8632001/2
Email: ssubramania@icipe.org
Nguya K. Maniania, Arthropod Pathology Unit, Email: nmaniania@icipe.org
Nyambo, Brigitte, Technology Transfer Unit,,bnyambo@icipe.org
6. Collaborating Institutions and Staff including NARS and German Partners
Kenya
Dr. M. Waiganjo, Kenya Agriculture Research Institute (KARI), Thika, Email:
monicahwaiganjo@yahoo.com
Uganda
Dr. Peter Sseruwagi, National Crops Resources Research Institute (NaCRRI), Namulonge,
Kampala Email: psseruwagi@yahoo.co.uk
Germany:
Prof. Dr. H. M. Poehling, Institute of Plant Diseases and Plant Protection, Gottfried Wilhelm
Leibniz Universitat, Hannover Email: poehling@ipp.uni-hannover.de
Prof. Dr. G. W. Moritz, Department of Developmental Biology, Martin-Luther-University of Halle-
Wittenberg, Halle (Saale) Email: moritz@zoologie.uni-halle.de
7. Project Description
The proposed project seeks to develop environmentally friendly control options for Western Flower
Thrips (WFT), Frankliniella occidentalis (Pergande) and other thrips in vegetable production systems in
East Africa. Thrips infestations cause huge losses in horticultural production in the region and current
control practices are exclusively based on the use of synthetic insecticides leading to resistance and
environmental contamination. The Project seeks to build on existing knowledge within icipe and its
partners and to address jointly the identified research gaps towards an environmentally friendly
management approach for thrips control. The project goal and long-term purpose are as follows:
Project goal:
Enhance food security and reduce poverty through sustainable crop production.

Project purpose:
Pest status of thrips greatly reduced by environmentally friendly control methods.
Output 1: Identity, importance and distribution of major plant infesting thrips studied in Kenya and
Uganda.
Output 2: Field ecology and dispersion of Frankliniella occidentalis studied on French beans in
Kenya.
Output 3: Metarhizium-based control product developed.
Output 4: Additional environmentally friendly control options tested in the greenhouse and field and
IPM strategy developed.
Output 5: Technology Transfer & Training program initiated with national partners.
8. Progress of activities
8.1 Brief summary of the various outputs
Output 1: Identity, importance and distribution of major plant infesting thrips studied in Kenya and
Uganda.
• Over 60 locations covering 12 districts distributed within five provinces in Kenya were surveyed
• Reference collections of more than 2100 slide mounted thrips specimens established. Database on
the alternate host plants for various thrips have been established
• Western Flower thrips (WFT), Frankliniella occidentalis was abundant in highlands,
Ceratothripoides sp, tomato thrips were found in the low semi arid regions
• WFT was a key pest on French beans, Bean Flower thrips, Megalurothrips sjostedti was found on
Lablab, cowpea and common bean, Ceratothripoides sp. was abundant on solanaceaous
vegetables and onion thrips, Thrips tabaci was widely present in Liliaceous and Cruciferous
vegetables
• Predatory thrips were found to be widely distributed however with very little abundance
• Chilli thrips, Scirothrips dorsalis yet another invasive pest from Asia was found to be distributed in
chillies, capsicum and bitter gourds.
Output 2: Field ecology and dispersion of Frankliniella occidentalis studied on French beans in Kenya.
• A Ph.D student from Kenya was recruited in January 2009. The second draft of the proposal has
been submitted for review by the supervisors in Hannover and icipe
• Field experiments to evaluate the field ecology and dispersion of WFT on French bean initiated in
December 2009 at KARI, Embu
Output 3: Metarhizium-based control product developed.
• A PhD student from Sénégal was recruited and joined the ARPPIS programme in October 2008.
The first draft of the proposal has been submitted for review
• Mass culturing of selected Beauveria bassiana and Metarhizium isolates and bioassays initiated
Output 4: Additional environmentally friendly control options tested in the greenhouse and field and
IPM strategy developed.
• Green house evaluation of botanicals against WFT have been initiated
• Field evaluation of influence of intercropping French bean with baby corn, sunflower and potato
initiated in December 2009
Output 5: Technology Transfer & Training program initiated with national partners.
• A taxonomic training on thrips collection and identification provided to members of the partner
institutes, quarantine organization, regional universities and East African Growers Association

• Thrips Identification software was provided to the partner institutes and quarantine organizations.
NaCRRI, Uganda contributes to the output 1; While KARI contributes to output 2 and 4.
9. Achievements and Constraints
9.1. Output 1: Identity, importance and distribution of major plant infesting thrips studied in Kenya and
Uganda.
Information on the thrips fauna and their importance in East Africa is very scarce. This information is
very important to prioritize the key pest thrips and target vegetable crops for formulation of region
specific and species specific management strategies. In this regard a nationwide survey on thrips fauna
associated with key vegetables and their associated plants were initiated in August, 2008 in Kenya.
Over 60 locations covering 12 districts distributed within five provinces (Nairobi, Central, Eastern, Rift
Valley and Western Provinces) in Kenya and in Kampala, Uganda were surveyed. More than 2100
thrips specimens have been collected, slide mounted, identified and a database established.
The important thrips species in terms of abundance, encountered in the survey were onion thrips,
Western flower thrips, tomato thrips, Ceratothripoides sp. and Bean flower thrips. Apart from the
important species listed above more than 20 terebrantian and many tubelliferan thrips were observed.
Onion thrips (Thrips tabaci, Lindeman 1988) was abundant both in the highlands (Gilgil, Naivasha
and Lari) and in upper midlands (Kajiado and Nairobi), and less abundant in lowlands of Yatta in Kenya
and Namulonge in Uganda. T. tabaci was a key pest of onion and cruciferous vegetables. This species
was collected from more than 44 host plant species belonging to 15 families.
Western Flower thrips (Frankliniella occidentalis, Pergande, 1895) was distributed in most of the
locations surveyed however they were quiet abundant in the highlands of Gilgil, Naivasha and Lari
divisions as compared to the lowlands (Yatta and Namulonge). The western flower thrips was a key
pest in French beans and tomato. This species was collected from more than 47 host plant species
belonging to 18 families.
Tomato thrips (Frankliniella schultezi, Trybom, 1910) is native to this region and it was distributed in
most of the locations surveyed it was more abundant in the lowlands of Yatta and Namulonge as
compared to the highlands. This species is widely found on French bean, potato and cucurbits. It was
observed in more that 52 plant species belonging to 21 families.
Ceratothripoides sp. was widely distributed in Embu, Kenya and in lowlands such as Athi River in
Kenya and Namulonge in Uganda. However it was significantly absent in the highlands of Naivasha,
Gilgil and Lari. This species was predominantly observed in solanaceous crops like tomato, potato and
eggplant, African nightshade etc. It was observed in 23 plant species belonging to 15 families.
Incidentally this native species has been intercepted by UK plant health Inspection service from Karela
exported from Kenya and notified in the EPPO in 2005.
The Bean Flower thrips (Megalurothrips sjostedti, Trybom, 1908) was widely distributed in
lowlands as compared to the highlands. The BFT was observed in more than 32 plant species
belonging to 14 plant families. This species as reported earlier was predominantly observed in
fabaceous crops such as French bean, common bean, broad bean, lablab etc. Among the other
species observed in the survey, the chilli thrips, Scirtothrips dorsalis was found to be distributed in the
lowlands on chillies, capsicum and bitter gourd. Specimens have been sent to Dr. Moritz for
confirmation of identity. Incidentally this species again is an invasive species with South Asia as the
centre of origin. This pest again was intercepted in 2003 by the UK plant quarantine from bitter gourd
exported to UK from Kenya. However no information on the distribution of this pest exists in Kenya.
More detailed survey on host plants and distribution of this species is needed.
Predatory thrips (Aeolothrips sp.), parasitoids and pirate bugs were the commonly encountered natural
enemies however less abundant.
Surveys in the next 6-10 months will cover the Coast, Nyanza, Western, Rift valley and Eastern
provinces in Kenya and more locations in Uganda.

9.2. Output 2: Field ecology and dispersion of Frankliniella occidentalis studied on French
beans in Kenya
Western flower thrips probably invades fields from infested plants in neighboring fields and field
margins. However, detailed knowledge on the spatial pattern of the invasion as well as on the
secondary spread in the field and influence of abiotic and biotic factors is not available. Experiments
within this output will address some the above research gaps and it will form a part of a Ph. D student
thesis jointly supervised by partners in University of Hannover.
A Ph. D student identified from Hannover participated in the planning meeting organized July 2008.
However the student subsequently declined to take up the offer. In this regard, prospective students
from Kenya and Uganda were screened and a student from Kenya has been selected in consensus
with partners in Hannover. The student joined the program in January 2009. The second draft of the
research proposal has been submitted for review by the supervisors in Hannover and icipe.
Large –scale and small scale farm fields have been identified in Thika and Embu to evaluate the
population dynamics of thrips in French bean over seasons. Surveys on the thrips diversity in Kenya
have revealed regional differences in distribution of key pest thrips. Evaluation of the population
dynamics over different seasons will provide us information on the seasonal variations. It will also
enable us to understand the influence of large-scale, high intensive and less diverse farming system as
compared to small-scale, low intensive and diverse farming system.
Field experiments to evaluate the population ecology and dispersion of WFT have been initiated in the
KARI, Embu in December, 2009. The influence of intercrops such as baby corn, sunflower and potato
on dynamics of thrips population on French bean will be simultaneously evaluated.
9.3. Output 3: Metarhizium-based control product developed.
Beauveria bassiana and Metarhizium anisopliae are potential microbial control agents that can be
utilized for management of thrips. Previous studies at icipe have led to the identification of a virulent
isolate of Metarhizium anisopliae (icipe69) against the bean flower thrips. Its efficacy has been proven
in the field against flower thrips, the onion thrips, the western flower thrips in cut flower and runner
bean, and at less extent against the western flower thrips on French bean.
A Ph.D student joined the ARPPIS programme in October 2008 to undertake activities pertaining to this
output. The student has submitted the first draft of the proposal for review by the icipe’s supervisors.
The student has already started culturing fungal isolates from the icipe’s Arthropod Germplasm Centre
and initiated bioassays against the WFT. Eight isolates of M. anisopliae and 7 isolates of B. bassiana
are ready so far for screening. Virulent B. bassiana isolates will be further screened for their endophytic
properties in selected host plants.
9.4. Output 4: Additional environmentally friendly control options tested in the greenhouse and
field and IPM strategy developed.
Green house experiments have been initiated in December 2009 for evaluation of botanical pesticides
such as neem, pyrethrum and garlic extracts for the management of WFT. Both soil and foliar
application of the above botanicals are evaluated. Further laboratory bioassays will be conducted to
screen for effective botanical pesticides.
Effectiveness of plastic mulches and live mulches for management of thrips will be evaluated in small
scale field trials to be established by Feb 2009. Based on the outcome of the above experiments, field
trials with French bean to evaluate the best treatments will be initated by June 2009.
Role of intercropping French bean with babycorn, sunflower and potato for the management of western
flower thrips will be evaluated, simultaneously with the field ecology experiments.

9.5. Output 5: Technology Transfer & Training program initiated with national partners.
Training on collection, processing and identification of thrips was provided by Prof. Gerald Moritz
immediately after the Project planning meeting. Members from partner institutes, KARI, UMU, KEPHIS,
regional universities like JKUAT, Kenya, Makerere University, Uganda and grower organization like
East African Growers, technicians and students likely to be involved in the project activities were
trained. Subsequently thrips identification software was also provided to organizations such as KARI,
KEPHIS, Kenya and NaCRRI, Uganda. Along with the identification softwares a refresher course on
identification of thrips was also organized in NaCRRI and KARI, Thika.
10. Conclusions for the following Reporting Period
Key pest thrips on various vegetables and regional differences in the diversity of the thrips complex
have been identified and further surveys are on-going. Complete information on the thrips diversity and
abundance in Kenya will be available by June 2008 when the surveys will be completed. Agreements
and work plans have been formalized with partners in Uganda and activities initiated in January 2009.
Representatives of partner institutes, regional universities, quarantine organizations and grower
organizations were trained on taxonomic identification of thrips. Activities pertaining to field ecology
studies, entomopathogens and cultural control of thrips have been initiated with greenhouse and field
experiments. Initial surveys revealed the prevalence of another invasive pest thrips, chilli thrips,
Scirtothrips dorsalis? in the agro-ecosystem especially on chillies and karela. More detailed studies on
the identity, distribution, ecology and extent of damage of this pest will be undertaken. To understand
the seasonal variations and impact of farm management practices on dynamics of pest thrips, identified
small and large scale farm holdings in different regions will be surveyed over seasons for thrips and
their natural enemies. Detailed investigation on the diversity and importance of tospoviruses vectored
by different thrips will also be carried out. Outputs from the survey will be utilized to develop a userfriendly
taxonomic tool for thrips complex in Africa and to identify prospective sites for exploration of
natural enemies for invasive pest thrips in their native centers of origin.
The implementation of the project activities were delayed during the first six months of 2008 due to the
departure of the previous project coordinator from icipe. However this delay in the implementation will
be suitably addressed with the progression of project activities.
11. Publications, Papers and Reports
CD-ROM of presentations and discussions at the 1 st project planning meeting, July 28 th – 29 th , 2008,
icipe, Nairobi, Kenya
CD-ROM of presentations and lectures delivered at the thrips taxonomy training program organized by
Dr. Gerald Moritz, Martin-Luther University, Germany for stakeholders, July 30 th – 31 st , icipe, Nairobi,
Kenya