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This study describes a glucocapparin determination method. Based on rapeseed determination of glucosinolate (GSL), the equation of the average straight regression line is Y = 100.42X – 0.03 (R2 = 0.9998). Enzymatic hydrolysis of glucocapparin extracted from leaves and fruits of B. senegalensis, analyzed by SPME-GC-MS confirmed the presence of methylisothiocyanate as the main hydrolysis glucocapparin product. Monitoring glucocapparin contents in B. senegalensis leaves and fruits collected in 4 localities in Senegal showed differences between organs according localities and periods of harvest. Glucocapparin content was very high in dry season particularly in January and the lowest rates were recorded during the rainy period between August and November.

Several technologies reputedly minimize losses of stored cowpea grain to bruchid beetles on low resource farms in Africa. Side by side comparison of these different postharvest storage methods can provide the basis for deciding which performs best. We compared six different technologies for cowpea storage: (1) grain mixed with ash; (2) mixed with sand; (3) fumigated with phostoxin; (4) admixed with the stems and leaves of Boscia senegalensis (Pers) Lam ex Poir, a potential botanical insecticide; (5) disinfested using a solar heater, and; (6) hermetically sealed in triple-layer plastic bags. Sampling was done at thirty-day intervals over five months of storage. Counts were made of (i) adult emergence holes, (ii) dead larvae and (iii) surviving bruchid larvae and adults. Controls, which consisted of infested cowpea grain stored in cloth bags, were damaged extensively. Boscia senegalensis -treated grain suffered similar severe damage. All other treatments suppressed bruchid population increases as was evident from the much lower counts of emergence holes and lower numbers of surviving or dead insects.

Boscia senegalensis is a drought resistant shrub whose seeds are used in West Africa as food. However, the seeds, or hanza, taste bitter which can be cured by soaking them in water for 4-7 days. The waste water resulting from the processing takes up the bitter taste, which makes it unsuitable for consumption. When used for irrigation, allelopathic effects were observed. Glucosinolates and their breakdown products are the potential causes for both the bitter taste and the allelopathic effects. The objectives of this study are to identify and quantify the glucosinolates present in processed and unprocessed hanza as well as different organs of B. senegalensis, to analyze the chemical composition of the processing water, and to pinpoint the causal agent for the allelopathic properties of the waste water. Hanza (seeds without testa), leaves, branches, unripe and ripe fruits were collected in three populations and subjected to glucosinolate analyses. Methylglucosinolates were identified in all plant parts and populations, with the highest concentrations being found in the hanza. The levels of methylglucosinolates in the hanza reduced significantly during the soaking process. Waste water was collected for 6 days and contained large amounts of macro- and micronutrients, methylglucosinolate as well as methylisothiocyanate, resulting from the conversion of glucosinolates. Waste water from days 1-3 (High) and 4-6 (Low) was pooled and used to water seeds from 11 different crops and weeds. The High treatment significantly delayed or reduced germination of all the plant species tested. Using similar levels of methylisothiocyanate as detected in the waste water, we found that germination of a subset of the plant species was inhibited equally to the waste water treatments. This confirmed that the levels of methylisiothiocyanate in the waste water were sufficient to cause the allelopathic effect. This leads to the possibility of using hanza waste water in weed control programs.

In West Africa Callosobruchus maculatus F. causes major losses during storage of cowpea (Vigna unguiculata Walper). The larvae of C. maculatus are parasitized inside the seeds by Dinarmus basalis (Rondani). African farmers introduce aromatic plants into storage systems at the beginning of the storage period that release toxic volatile compounds into the headspace of the stores. The susceptibility of C. maculatus and D. basalis to two plant sulphur-containing compounds, methylisothiocyanate (MITC) and dimethyl disulfide (DMDS), was analyzed under laboratory conditions. The adults of C. maculatus and D. basalis had the same susceptibility to MITC but the parasitoid was more susceptible to DMDS than its host. The larvae were less affected by the treatments than the adults; the seed coat acts as a barrier for volatile penetration. Susceptibility to DMDS was high when the C. maculatus larvae were extracted from the seeds. DMDS was more toxic than MITC and differences in penetration inside the seeds could explain these results. The higher susceptibility of D. basalis to the treatments could have consequences on biological control in storage systems. The presence or absence of leaves of the shrub Boscia senegalensis Lamarck (Capparaceae), which release MITC into the jar atmosphere could have an impact on numbers of C. maculatus and D. basalis. When D. basalis adults were put into the storage systems in the absence of B. senegalensis leaves, successive generations of the parasitoids maintained the C. maculatus population at a low density. In the presence of B. senegalensis leaves, the D. basalis population was more affected by the treatment than its host C. maculatus and was incapable of preventing the increase in bruchid population. This traditional method appears to increase seed weight losses by limiting the efficiency of the biological control.

The bruchid Callosobruchus maculatus causes major losses during the storage of the seeds of Vigna unguiculata in West Africa. An endemic parasitoid, the pteromalid Dinarmus basalis is present in the stores and can reduce the increase in bruchid populations. African farmers often place in the stores the leaves of a shrub, Boscia senegalensis Lam.(Capparaceae), which release methylisothiocyanate (MITC). This compound is toxic to adult bruchids and could reduce seed losses but its influence on the bruchid natural enemy D. basalis was hitherto unknown. The susceptibility of C. maculatus and D. basalis to MITC was assessed under laboratory conditions. The susceptibility of adults of both species towards MITC were similar. After a 24 h exposure, the LC 50 was respectively 0.48 and 0.54 mg/l for C. maculatus and D. basalis . The ovicidal activity of this compound was high; the LC 50 of C. maculatus eggs was 0.04 mg/l after a 24 h exposure to MITC. High MITC concentrations only slightly affected the survival of C. maculatus during its post-embryonic development in the seeds of V. unguiculata . Gas chromatographic analysis demonstrated that 25–35% of the MITC present in the atmosphere of the experimental jars was absorbed by the seeds but concentrations inside the cotyledons were too low to influence the survival of the C. maculatus larvae. The D. basalis larvae developing at the expense of their host inside the larval galleries, were more affected by the treatment. The introduction of B. senegalensis releasing MITC in the storage systems could reduce the density of the parasitoid population and so increase the seed losses by permitting the development of the bruchid population.

The effect of hermetic storage alone or in combination with Boscia senegalensis has been evaluated against Callosobruchus maculatus . Analysis of gas concentrations within a 7-day period indicated that O 2 declined from 19.2 to 2.3% and CO 2 rose from 1.2 to 22.8%. Prolonged storage durations increased adult mortality, significantly increased the developmental time and induced 60–80% reduction in the F1 progeny. The use of hermetic storage in combination with B. senegalensis fruits, at 1.2 g/l (flask volume) reduced the emergence of the cowpea beetle, while 2.4–4.8 g/l completely inhibited the production of a new generation of C. maculatus .

In this study, we examined the toxicity and persistence of ground fresh leaves of B. senegalensis on the development of Callosobruchus maculatus , major insect pest of cowpea ( V. unguiculata ) in the sahelian area. The effect of the product has been evaluated over the three developmental stages (egg, larvae and adult) of C. maculatus . At high concentration (4 g/l of ground leaves), 100 % of adults were killed within 24 h of exposure to the leaf extract, and the development of newly laid eggs and neonate larvae was also inhibited. However, the ground leaves of B. senegalensis have a variable efficacy against the bruchid instars larva. The 2nd larvae stage (L2) of C. maculatus developing inside the seeds have proved to be highly susceptible while the 4th larval stage was relatively tolerant. The study of the toxicity persistence of the leaves of B. senegalensis showed that whatever its concentration, the efficacy of crushed leaves of B. senegalensis decreased with the storage time. At a concentration of 20 g/l, the effect of B. seneglensis can persist up to 7 days. Keywords : Biopesticides, Bruchids, cowpea, pest control, Niger

This report describes in vitro micropropagation of Boscia senegalensis, so-called famine foods, that helped the people in Darfur and Kordofan, Sudan survive during the 1984–1985 famine. Four types of explants prepared from green mature zygotic embryos were cultured on Murashige and Skoog (MS) medium augmented with 1–5 mg/L 6-benzyladenine (BA). The highest number of shoots per explant (14.3±0.9) was achieved on MS medium supplemented with 3 mg/L BA, while the highest shoot length [(3.5±0.4) cm] was obtained with 1 mg/L BA. The shoot cluster, when subcultured to its same medium, significantly increased the rate of shoot multiplication by the end of the third subculture. The maximum mean number of shoots per explant (86.5±3.6) was produced after three multiplication cycles on 3 mg/L BA-supplemented medium. In vitro induced shoots were excised and rooted on half strength MS medium fortified with 0.25 mg/L indole-3-butyric acid (IBA) to obtain complete plantlets. B. senegalensis-regenerated plantlets obtained in vitro for the first time, were hardened and 95% survived under greenhouse conditions.

Seeds of four African tree species from the Sahelian zone (Boscia senegalensis) and the Sudanian zone (Butyrospermum parkii, Cordyla pinnata and Saba senegalensis) lose viability after moisture contents drop below 22 and 30%, depending on the species. Seed longevity in wet and airtight storage does not exceed a few months. Temperatures close to zero elicit symptoms of chilling injury leading to rapid seed death. The optimum storage temperature is 15°C. These results allow the four species to be classified as recalcitrant seed species. Boscia senegalensis is therefore an exception in arid zones where most species have orthodox seeds.

B. senegalensis leaves and fruits are known to contain glucocapparin which hydrolysis by endogenous myrosinases lead to the release of methylisothiocyanate (MITC). This product is very active against insect stored products by fumigation. This paper reveals that MITC penetrate into seeds during treatment. Multiple Headspace Extraction coupled to GC (MHE-GC) method allowed to evaluate the level of MITC residues sequestrated by exposed seeds to B. senegalensis organs. Furthermore, tests conducted on germination capacity have been demonstrated that MITC doesn’t corrupt the germination capacity of grains.