Three stepping stones leading to malaria elimination, changing world maps on the way.

Over the course of human history, malaria has been one of the deadliest tropical diseases encountered by humans. Malaria exerts a far more profound influence on progress toward a peaceful life in a given country than have any of the acute epidemic diseases, such as yellow fever. This is because a population stricken with malaria may suffer two negative pressures: acute fatalities from severe malaria, particularly in young children, and long-lasting debilitating symptoms and socio-economic impacts of recurrent and persistent malaria. Here, we present three successive historical stories, stepping stones, the second and third stones having learnt from the previous one, and which was to eventually lead to successful malaria elimination. Each country map tells its own story of change made possible only by an anti-malaria activity.

Potential use of neem leaf slurry as a sustainable dry season management strategy to control the malaria vector Anopheles gambiae (DIPTERA: CULICIDAE) in west African villages.

Larval management of the malaria vector, Anopheles gambiae Giles s.s., has been successful in reducing disease transmission. However, pesticides are not affordable to farmers in remote villages in Mali, and in other material resource poor countries. Insect resistance to insecticides and nontarget toxicity pose additional problems. Neem (Azadirachta indica A. Juss) is a tree with many beneficial, insect bioactive compounds, such as azadirachtin. We tested the hypothesis that neem leaf slurry is a sustainable, natural product, anopheline larvicide. A field study conducted in Sanambele (Mali) in 2010 demonstrated neem leaf slurry can work with only the available tools and resources in the village. Laboratory bioassays were conducted with third instar An. gambiae and village methods were used to prepare the leaf slurry. Experimental concentration ranges were 1,061-21,224 mg/L pulverized neem leaves in distilled water. The 50 and 90% lethal concentrations at 72 h were 8,825 mg/L and 15,212 mg/L, respectively. LC concentrations were higher than for other parts of the neem tree when compared with previous published studies because leaf slurry preparation was simplified by omitting removal of fibrous plant tissue. Using storytelling as a medium of knowledge transfer, villagers combined available resources to manage anopheline larvae. Preparation of neem leaf slurries is a sustainable approach which allows villagers to proactively reduce mosquito larval density within their community as part of an integrated management system.

Water quality and waterborne disease in the Niger River Inland Delta, Mali: a study of local knowledge and response.

This paper presents the findings of a study to assess patterns in local knowledge of and response to water quality and waterborne diseases in relation to seasonal changes in the Niger River Inland Delta. The study draws on field data collected in four villages along the Niger River in the Mopti region of Mali during September 2008. The major findings suggest: (1) water use behaviors and diarrheal disease management are influenced by the tremendous seasonal fluctuations in the riverine environment; (2) local awareness of the relationship between poor water quality, oral-fecal disease transmission, and waterborne disease is low; (3) interventions to mitigate the high incidence of childhood diarrhea and degraded water quality are limited by ongoing socio-economic, cultural, and environmental factors; and (4) women's level of health knowledge is socially and culturally dependent.

Effects of steam-distilled shoot extract of Tagetes minuta (Asterales: Asteraceae) and entomopathogenic fungi on larval Tetanops myopaeformis.

Interactions of a biopesticidal formulation of steam distilled shoot extract of Mexican marigold, Tagetes minuta, and entomopathogenic fungi were evaluated for management of the sugarbeet root maggot, Tetanops myopaeformis (Röder). Shoot extract plus surfactant (E-Z Mulse) (=T. minuta oil) was used in a 65:35 ratio to test the hypothesis that this fungicidal and nematocidal biopesticide causes dose-dependent mortality and developmental arrest of T. myopaeformis but does not interfere with the action of entomopathogenic fungi when applied together. A soil-petri dish bioassay system was developed to test the hypothesis. For diapausing, nonfeeding but active 12-mo-old third-instar larvae, 0.5% T. minuta oil treatment (=0.325% active ingredient [AI]) was sufficient to prevent pupation without mortality, but 0.75% T. minuta oil treatment (=0.458% AI) was lethal for 93% of the test insects. The effect of T. minuta oil on fungal efficacy under simultaneous use was studied using a model system of two entomopathogenic fungi, Beauveria bassiana (Bals.) Vuillemin. TM28 and Metarhizium anisopliae variety anisopliae (Metsch.) Sorokin MA 1200, in a soil-based bioassay with larval sugarbeet root maggots. No adverse effects of T. minuta oil on action of entomopathogenic fungi and no synergy were found; an additive effect of the T. minuta oil and each fungal isolate separately was found.

Insect management products from Malian traditional medicine--establishing systematic criteria for their identification.

In material-resource poor countries like Mali, traditional practices incorporate the use of plants for medicinal purposes. Ethnobotanical research has documented traditional uses of plants, while concomitant studies by natural product chemists, ethnobotanists, and microbiologists have verified the efficacy of using traditional medicinal plants that have proven antimicrobial activity. These plants may also be used to protect agricultural crops pre-harvest and post-harvest from insect herbivory. In Mali, subsistence farmers, regional scientists, and extension specialists rely on local plants for many medicinal needs and are amenable to using traditional plant materials for insect pest management. The goal of this research was to develop Integrated Pest Management (IPM) strategies using Malian traditional medicine as a discovery lead. The discovery premise was based on identifying plants through a matrix approach utilizing agricultural scientists, traditional practitioners, and subsistence farmers. We hypothesized that plants used in traditional medicine with antimicrobial activity lead to potential insect pest management agents. To test our hypothesis, we developed a four-step process for selecting Malian plant species. Seven criteria were selected to create a systematic matrix to identify the most promising plant materials for practical, affordable, ecologically-sound insect management by Malian farmers. In the first step of the process, we developed a list of 294 medicinal Malian plant species which were evaluated using the matrix. Sixty-seven plant species met our main criteria. After the environmental soundness of these species was evaluated using four minor criteria, 50 species emerged from this pre-chemical, pre-bioassay process for further consideration in IPM programs in Mali.

Interactions of wheat variety, production environments, and prior insect damage on postharvest resistance to the lesser grain borer.

Wheat, Triticum aestivum L., varietal resistance to the lesser grain borer, Rhyzopertha dominica (F), was evaluated in hard spring wheat produced in 2001 and 2002 (Bozeman, Moccasin, and Huntley, MT). We tested the hypothesis that seed coat factors, not the endosperm, cause feeding resistance to R. dominica and that this resistance is genetic, not affected by agronomic conditions. Using a rapid, intensive feeding bioassay (frass production), we found, with one exception, no significant difference in resistance to R. dominica, among sound kernels of hard red wheat, comparing all locations and cultural conditions (irrigated versus dryland production). The most significantly resistant samples as indicated by lowest feeding activity (measured by lowest frass production) were 'Amidon' produced at Moccasin under dryland conditions and Amidon produced at Huntley under irrigated conditions. As with previous studies done in our laboratory, sound kernels of all hard wheat varieties from these new crop year studies (2001, 2002) were attacked. When subsamples of these varieties from the same locations and cultural conditions as the previous test were first subjected to a heavy infestation of Plodia interpunctella (Hübner) and then to the same age adult R. dominica, damage was significantly greater. Each kernel chosen for this test had been equally damaged by P. interpunctella larvae, germ consumed, endosperm not damaged, but fully exposed behind germ, no other damage. This collaborative damage caused feeding damage by R. dominica to increase 2- to 7.5-fold (as measured by R. dominica frass production). Particularly notable was 'McNeal' that switched from one of the most resistant varieties to the most fed upon, when the endosperm was exposed by P. interpunctella larvae. Therefore, we confirmed that at least one factor conferring resistance in McNeal is located in the kernel pericarp.

Development of a bioassay system for the predator, Xylocoris flavipes (Heteroptera: Anthocoridae), and its use in subchronic toxicity/pathogenicity studies of Beauveria bassiana strain GHA.

Microbial biocontrol agents are useful commercially only if they do not harm other natural biocontrol organisms, at recommended use rate in the environment where the microorganism is being used. To test the hypothesis that the predatory warehouse pirate bug, Xylocoris flavipes (Reuter), is not adversely affected by the entomopathogen, Beauveria bassiana (Balsamo) Vuillemin strain GHA, we developed a method using individually confined bugs during a 10-d feeding regime. Three concentrations of a conidial suspension were applied to assay surfaces (filter paper disks) to achieve 2.7 x 10(7), 2.6 x 10(6), and 2.6 x 10(5) conidia per cm2, representing 100X, 10X, and a field rate of 2.6 x 10(13) conidia per ha (+/-10%), respectively. Fifth instar X. flavipes suffered 0% infection at the field rate when confined to treated filter paper for 10 d (16% and 42% infection, respectively, at 10X and 100X the field rate). Second instar migratory grasshoppers, Melanoplus sanguinipes (F.), exposed to the same doses suffered 97, 92, and 100% mortality at the three respective doses 10 d after exposure. These data indicate that B. bassiana can be used safely at recommended application levels without significant effect on fifth instar populations of X. flavipes.

Postharvest resistance in hard spring and winter wheat varieties of the northern Great Plains to the lesser grain borer (Coleoptera: Bostrichidae).

Wheat (Triticum aestivum L.) varietal resistance to the lesser grain borer, Rhyzopertha dominica (F), was evaluated in hard spring and winter wheat produced 1997, 1998 (Bozeman, Montana). We tested the hypothesis that six Montana-grown spring wheat varieties, 'Ernest', 'Scholar', 'Hi-Line', 'McNeal', 'Newana', and 'Amidon', were equally and strongly resistant to R. dominica at low moisture contents (9-10%). Mortality/Feeding damage occurred in all varieties. In most assays, Ernest had significantly greater feeding damage from R. dominica than other varieties, usually not significantly different from the susceptible control. Mean adult mortality was significantly greater in McNeal (93%) and Hi-Line (92%) than in Ernest (34%) and Montana-grown, soft white spring wheat (Penawawa), the susceptible control (36%). In 9 wk, twice as many adult progeny were produced on Ernest than on McNeal, Hi-Line, or Scholar. We also compared three Montana-grown winter wheat varieties for resistance to R. dominica attack at low moisture contents (9-10%). Significantly more mortality after 6 wk was associated with all winter wheat varieties than the susceptible control. In 'Nuwest', 'Rocky', and 'Vanguard', significantly fewer progeny were produced than in the susceptible control; these varieties appeared more resistant. 'Tiber' and 'Neeley', in contrast, appeared more susceptible than other winter wheat varieties evaluated. Susceptibility decreased significantly with a 1.2% decrease in moisture content. Percentage of total protein was positively correlated with percentage of sound kernels and negatively with total progeny (r2 = -0.69). Kernel hardness was positively correlated with percentage of sound kernels, but negatively correlated with total progeny (r2 = -0.87) and dry weight loss.