PAPER SESSION X: MANAGEMENT AND CONTROL OF MITES AND TICKS

CHAIRPERSON: Dr. D.P. Kariuki

LEAD PAPER 4

THE STATUS OF MITE CONTROL IN KENYA

Prof. R.W. Njeru

University of Nairobi, P.O. Box 30197, Nairobi Kenya

no abstract available

PAPER 37

POTENTIAL NEW AMBLYOMMA VARIEGATUM CONTROL METHODS DERIVED FROM THE STUDY OF THE RELATIONSHIPS BETWEEN THE TICK AND ITS CATTLE HOST

F. Stachurski.

Centre International de Recherche-Développement en zone Sub-humide (CIRDES), BP454, Bobo-Dioulasso, Burkina Faso, E-mail: stachurski@fasonet.bf

From the results of the various studies carried out in Cameroon and Burkina Faso on the relationships between cattle host and the tick Amblyomma variegatum detailed in other presentations, only two control methods may be proposed to the traditional West African livestock farmers in order to control the tick infestation. These methods are not expensive, do not lead to important modifications of the traditional management practices, and should allow an important limitation of cattle infestation. A more rational frequentation of the harvested crop fields, where cattle are grazing stems, stalks and leaves at the beginning of the dry season, may thus be proposed as an ecological tick control method, because it has been observed that engorged nymphs fall off the hosts mainly during the afternoon (80% between 14 h 30 and 17 h 00). A herd management aiming at grazing on the savannahs during the mornings and on the residual crops only during the afternoons and not during the whole day as it is presently done may consequently lead to an important decrease of the dissemination of engorged nymphs on the natural pastures. Following the identification of the invasion process of cattle by the tick, it is assumed that a targeted treatment of the feet should allow a good control of the infestation because it was observed that the ticks picked up by the hosts on the pasture attach temporarily near the hooves, and reach the predilection sites (inguinal area, chest, axilla) only when the animals are lying down. As the traditional management practices do not enable the cattle to lay down during the day (the herds are brought onto the pasture approximately from 9 a.m. to 6 p.m.), almost all the ticks captured are still attached to the limb ends when the cattle are brought back to the night pen. The use of a foot-bath may therefore greatly reduce the cattle infestation, with only small quantities of chemicals. First successful trials were implemented in traditional herds.

PAPER 38

Effect of different neem formulations on spider mites (Tetranychus urticae)

M. Knapp¹ & S.S. Kashenge²

¹International Centre of Insect Physiology and Ecology (ICIPE), P.O. Box 30772, Nairobi, Kenya, E-mail: mknapp@icipe.org

²Sokoine University of Agriculture, P.O. Box 3000, Morogoro, Tanzania

The effects of for different commercially available neem formulations and one combination of a neem formulation and a chemical acaricide (Mitac) on Tetranychus urticae were tested in laboratory trials at ICIPE. Tomato leaf discs where dipped in different concentrations of the formulations. After air drying, 15 adult females of T. urticae were introduced on the discs and mortality was assessed after 24 hours. The LC₅₀ was 27.8 g/l for Neemros, 11.4 ml/l for Neemroc, 5.3 ml/l for Saroneem, 0.9 ml/l for Neemroc Combi and 1 ml/l + 15.7 g/l for the combination of Mitac and Saroneem. In another trial the efficacy of the different formulations was compared and Mitac was included as a check. The combination of Mitac and Saroneem caused he highest mortality after 24 hours (83.3%) followed by Neemroc (78.3%), Mitac (60.3%) Saroneem (53.4%) Neemroc Combi (38.9%) the control (treated with water) (4.5%) and Neemros (0.0).

PAPER 39

Management strategy for mites in flowers and potential for biological control

J.J. Anyango

KARI - NARL, P.O. Box 14733, Nairobi, Kenya

Commercial flower production has a few important pests displaying a range of biological features. The mite complex was studied on three varieties of carnation (i.e. Finesse, Optima and White Barbara) in a flower farm in Kenya. The mites species concerned are Tetranychus cinnabarinus, T urticae, and Aculops spp. Research initially concerned only specific soil pest fumigation, however, evidence of moderate to lower mites population on treatments that catered for sustainable plant health management (PHM) became clear prompting this project. For over a period of 18 months, carnations established in soil-less substrate (pumice in gunny bags), harboured five mites on average as compared to plants grown on bare soil that harboured over 20 mites from 10 leaves, whether the crop was judiciously or prolifically sprayed using acaricides. The study further established that there is economic advantages from judicious compared to prolific chemical spraying despite the fact that they were both effective for the control of mites. White Barbara variety harboured higher mite numbers compared to Finesse or Optima in all the treatments, an indication that the latter could be more resistant to mite attack. The results further showed higher marketable flower harvests with fewer rejection from pumice substrate plots whether judiciously or prolifically sprayed as compared to bare soil treatments. Economic analysis for using the soil-less substrate and judicious spraying programmes revealed a fundamental financial gain if the method can be adopted as compared to present farmer practice of prolific chemical applications. Adopted alternative substrate approach to pest control was found to hold promise for biological control as plots where pumice was used and sprayed judiciously were found to harbour some Phytoseiidae  and Orius spp. predators. The body of knowledge assembled from this study shows that there is potential of using biological as well as host-plant resistance in combination with other sustainable plant health management to make a synthesis (modelling) that may be used to solve flower farmer problems a part from opening new avenues for future research.

PAPER 40

Red spider mites (Tetranychus evansi) in tomato: implications for the small scale grower in Zambia

S.W.S. Luchen¹, D.S. Mingochi¹, M Taguma² and M. Knapp³

¹National Irrigation Research Station, P/B S-3, Mazabuka, Zambia, E-mail swsluchen@hotmail.com

²Mt. Makulu Central Research Station. P/B 7, Chilanga, Zambia.

³International Centre of Insect Physiology and Ecology (ICIPE), Nairobi, Kenya. E-mail mknapp@icipe.org

Pests and diseases are among constraints that limit production of tomato (Lycopersicon esculentum Miller), a crop of nutritional and socio-economic importance in Zambia. Red spider mite (RSM) which was first reported in the early 1980ies is now recognised as the most important pest of tomato among small-scale farmers. Evaluation of chemical and biological methods against RSM in the mid 1980ies indicated the acaricide Omite (Propargite) was effective against the pest. Its use was, however, restricted by cost and local availability. Use of the predacious mite Phytoseiulus persimilis against the pest proved unsuccessful in field studies. The persistence of the mite problem into the late 1990ies and observed limitations of past control approaches necessitated a review of past research work and collection of baseline data on RSM. A survey to collect small-scale farmer's indigenous knowledge and perception of the RSM problem was thus undertaken in 1999. The survey showed that most farmers sampled (97 %) relied on commercial pesticides for RSM control. Some of the pesticides (40 %) mentioned by the farmers are inappropriate for mite control. Pesticide application decisions by farmers are largely based on signs of pest/disease attack (44 % of respondents) or fixed regime sprays (33 % of respondents). At least 39.3 % of the respondent farmers had knowledge of other non-chemical RSM management options. Some of the farmers (23 %), felt that there existed some differences in the tolerance of cultivars to RSM, though the majority did not think so (47.5 %). A small proportion of farmers had observed beneficial organisms against RSM in tomato and other Solanaceae including Oligota spp and coccinellids. Taxonomic identification of mite specimens collected during the survey suggests that the most important species in the surveyed areas is the tobacco mite Tetranychus evansi and not Tetranychus urticae Koch as previously believed.

PAPER 41

EPIDEMIOLOGY OF HUMAN DEMODICOSIS OBTAINED FROM THE ATTENDANCE DATA IN A LARGE-SCALE INDUSTRY CITY

O.E. Akilov

Department of Skin and Venereal Diseases, Ural State Medical Academy, Center of Medical Cosmetology "Aesthetics", Ekaterinburg, Russia, E-mail: oakilov@mail.ur.ru

Human demodicosis is a chronic mite's dermatosis caused by Demodex folliculorum and Demodex brevis, which are obligatory ectoparasites of hair follicles and sebaceous glands. The objective of this study was to estimate the prevalence and primary morbidity rate of human demodicosis obtained from the attendance data in a large-scale city of the Russian Federation. We used the data accumulated from the annual reports of the Ekaterinburg City Dermatovenereology Dispensary during the 8 years from 1992 to 1999. The prevalence and primary morbidity rate of human demodicosis in the Lenin and October Districts has been studied. The average annual number of the population in the Lenin District is 167,500 persons; in the October District: 149,500 persons. The summary data on morbidity of human demodicosis in the 2 districts is included in the table below:

year	Prevalence of human demodicosis (in 100,000 persons)	Primary morbidity rate of human demodicosis (in 100,000 persons)
1992	29.6	17.0
1993	30.0	17.2
1994	35.8	17.4
1995	32.9	19.5
1996	39.9	19.9
1997	53.4	16.8
1998	45.2	16.5
1999	44.8	16.5

The primary morbidity rate of human demodicosis does not fluctuate significantly as a whole, but is an approximately constant average of 16.6:100,000 persons a year (standard deviation ±1,4; mean error ± 0,5). The prevalence of human demodicosis is a value more unstable and can be described by the presence of the periods of rises and declines of morbidity. These specify the presence of a dependence upon the relapses and exacerbation of disease from the external factors: ecological situation, changes of a temperature, humidity, solar activity etc.