Local Uses and Parasitism of Loranthaceae in Sudano-Sahelian Zone of Cameroon: Case of Diamare Plain in Far North Region

The Loranthaceae, commonly referred to "mistletoe from Africa” are used by communities of Cameroon for their numerous therapeutic virtues. The study examined the local various uses of Loranthaceae species in Diamare plain of Cameroon. Participatory rural appraisal method was used with 130 persons, namely traditional healers, breeders, farmers and foresters in order to identify the local uses of Loranthaceae species. We used itinerary botanical survey method in thirty-two (32) villages for the inventory of Loranthaceae species. In each village, two (02) itineraries (1000 m x 20 m) were realized on account of one itinerary in an agrosystem and one itinerary in a natural site. Results revealed five categories of uses of Loranthaceae: human traditional pharmacopoeia, fodder, magical use, ritual use and veterinary medicine. Knowledge of Loranthaceae uses was broadly influenced by age of respondents, traditional healers and people over 41 years old were the major libraries of knowledge on Loranthaceae. Human traditional pharmacopoeia (96.92%) and magical use (82.30%) were the most important categories of uses. Nine Loranthaceae species were inventoried in natural and agrosystem sites, namely Agelanthus dodoneifolius (DC.) Polh. & Wiens, Tapinanthus globiferus (A. Rich.) Tiegh., T. oleifolius (J.C.Wendl.), T. ophiodes (Sprague) Danser and T. voltensis Van Tiegh. ex Balle, Phragmanthera sp., Tapinanthus sp1., Tapinanthus sp2. and Tapinanthus sp3. . The most parasitized species with high rate of parasitism and vulnerability were Ziziphus mauritiana Lam. (58.33%; 6.98%), Acacia albida Del. (45.03%; 13.97%), Azadirachta indica A. Juss. (39.05%; 18.03%), Psidium guajava L. (29.62%; 5.10%) and Citrus limon (L.) Burm. f. (26.31%; 6.36%). Rate of parasitism and rate of vulnerability were positively but weakly correlated (Kendall, r = 0.09).


Introduction
African forests are a huge reservoir of biological diversity and their ecological functions are essential for humanity. Forest formations play an important role in meeting many of the basic needs of local populations. They provide wood and energy and help to cover the nutritional needs of various social groups. Likewise, they represent the main source of medicinal products in rural areas and participate in local and national economies (IPGRI, 1999). Thus, the medicinal and nutritional nature of these plant resources places them at the heart of any human activity requiring clear conservation. Unfortunately, this conservation is destroyed by the attack of plants of the Loranthaceae family (Bright and Okusanya, 1998;Ayuba, 2000;Bako et al., 2001;Wahab et al., 2010). Loranthaceae, designated under the common term of "African mistletoe", are phanerogams, chlorophyllian hemiparasites or epiphytes which, implanted on the aerial parts of their hosts, are responsible for economic, ecological, morphogenetic and technological damage variable according to the cultures or parasitized woody species (Sallé et al., 1998). These hemiparasites are plants that have lost their autonomy in accessing nutrient resources during their evolution and have become dependent on their hosts. They attach themselves to their hosts through a specific organ called a haustorium or sucker which establishes contact with its host at the level of xylemic connections (Sallé et al., op. cit.). Several studies carried out on Loranthaceae in Africa showed that they drastically reduce the productivity of their hosts (Boussim, 2002;Edagbo et al., 2013;Massako et al., 2013). The latter represent a real scourge against which a proactive fight is essential, given the extent of the damage. Faced with this situation, Boussim et Medah (2004) tested several methods of combating these hemiparasites in Burkina Faso. The most applicable methods are mechanical control, biological control and the selection of resistant varieties. Sallé and Aber (1986) mentionned that such a struggle necessarily requires better knowledge of the geographic distribution and the biology of the target organisms. However, the systematic eradication of Loranthaceae would not be very reasonable since these plants are in great demand by the populations especially for their therapeutic potentials (Jiofack et al., 2010;Ogunmefun et al., 2013;O'neill et Rana, 2016). This makes these plants an asset for the development of the African pharmacopoeia, so that their large-scale use as a biological control method has been recommended (Jiofack et al., 2010). From one region to another, their use in therapy manifests itself either in isolation, or according to an appropriate or specific host, or finally in combination with other drugs or solvents (Jiofack et al., 2009 Rana, 2016). It emerges from all their work that the Loranthaceae are used not only in traditional medicine but also for fodder, human food, the manufacture of ritual objects and as material for capturing birds. The major problem is the fight against poverty and undernourishment, in connection with an explosive demography which is at the origin of the disappearance of forest recruits. This situation is at the origin of agroforestry plantations and house gardens, in which fruit trees are very often attacked by numerous phytoparasites. The latters are sometimes underestimated by the peasants, although they cause a lot of damage to their crops. However, Loranthaceae appear to be a panacea for the evils which weigh on the population because of its therapeutic and fodder virtues. In Cameroon, some surveys were conducted on socio-economic importance of the Loranthaceae and the parasitism in equatorial zone (Dibong et al. 2008;2009;Feguem, 2011;Azo'o et al., 2013). Studies in the sudano-sahelian zone on Loranthaceae are still to be carried out. The survey aims at examining the local uses of Loranthaceae species and their potential existing in sudano-sahelian zone of Cameroon in view of their sustainable management.

Materials and methods Study site
The study was carried out in the Far-North Region of Cameroon, in the Diamare plain including Mayo-Kani and Diamare Divisions. These Divisions cover a total area of 6450 km² and a population of 768 603 inhabitants (MINATD, 2010). It is located between 10°0' N to 10°48' N and 14°0' E to 14°48' E ( Fig. 1).The climate is of the Sudano-sahelian zone and is characterized by two seasons, a long dry season (8 to 9 months) spanning from October to May and a short rainy season (3 to 4 months) from June to September (Fotsing, 2009). Very high temperatures reaching 45°C under shade and a very dry atmosphere are experienced from March to June (MINATD, 2010). Rainfall varies between 600 and 900 mm/year, with maximum rainfall mostly between July and August (Djibrilla, 2016). Hydrography is made up of temporal flowing rivers (Mayos) which dry up at the end of the rainy season. The main soil types encountered are vertisols, hardés, sandy soils, rocky soils in mountain areas, and silty soils favorable to market gardening (FAO, 2011 (Wafo, 2008). Other African mistletoe and Acacia albida are appreciated for their leaves serving as fodders and their fertilizing roots. Fertile soils are indicated by the presence of Acacia albida (Djibrilla, 2016). The wildlife is poor and is endangered due to the lack of a conducive environment for their development. Some species are mostly located in the mountains, and include rodents (mice, rats, damans, squirrels, hares); reptiles (lambs, lizards, snakes); locusts and caterpillars; sparrows; hyenas; panthers and wild cats; monkeys (IPCC, 2007). Most of the people rely on agriculture, livestock and forest resources to meet their basic needs.

Data collection Determination of local uses of Loranthaceae in Diamare plain
The uses of Loranthaceae were determined through ethnobotanical surveys with the local populations in thirty-two (32) villages. Participatory rural appraisal method (Shillington, 2002) was performed with 130 persons aged from 20 to 88 years, 104 (81%) men and 26 (19%) women. The target groups were constituted of traditional healers (23), pastoralists (57), farmers and/or foresters (50). Traditional rulers were highly involved in the choice of the actors. With these target populations, semi-structured (individual) and structured interviews (focus group discussions) were realized concerning the knowledge of Loranthaceae and their hosts, and the indigenous uses made of these hemiparasites (Grangé et Libart, 1992). During the focus discussions, each member was free to comment, to criticize or to speculate on the views expressed by the previous speakers.

Inventory of Loranthaceae and their hosts in agrosystems and natural sites
Loranthaceae and their host species were identified using the itinerary botanical survey method (Konadio, 2007) in the areas indicated by the respondents in thirty-two (32) villages. The villages were chosen on the basis of the presence of agrosystems and natural sites in the localities. In each village, a planted site or orchard and a natural site were sampled, and an itinerary botanical survey (1000 m x 20 m) was realized in each plant formation. In the various itineraries, all parasitized trees were censused and identified, and the number of tufts was counted. Loranthaceae specimens were collected, identified and/or confirmed with the help of volumes on Loranthaceae in "Flora of Cameroon" (Balle, 1982) and in "Trees, shrubs and lianas of dry areas in West Africa (Arbonnier, 2000).

Data processing and analysis
For each plant tree, the rate of parasitism was calculated (Massako et al., 2013): Where RP is the rate of parasitism. The rate of vulnerability was calculated for each species following the formula (Massako et al., 2013): Where RV is the rate of vulnerability. The variation of parasitism between natural sites and agrosystems was realized by using Analysis of Variance (ANOVA) at the level of 0.05. All the statistical analyses were performed with Origin 6.0 Sofware.

Local uses of Loranthaceae in Diamare plain
Local populations of Diamare plain are unanimous on the therapeutic virtues of Loranthaceae species. They are involved in five (05) categories of uses: human traditional pharmacopoeia, veterinary medicine, fodder, ritual and mystical uses. Human traditional pharmacopoeia and magic were the most important categories of uses (96.92% and 82.30% respectively). In terms of traditional human medicine, sterility, painful periods and mental disorders were recognized by all traditional healers as ailments treated by Loranthaceae species. The other diseases treated by the hemiparasites were malaria, darter and ringworm. For magical uses, traditional healers and the elders enumerated luck, magic spells, madness and bewitchment. Veterinary medicine was less used according to respondents, with a rate of 1.53% (Figure 2). At the level of 0.05, the means were significantly different (ANOVA, p < 0.05). This difference can be explained by the diversity of ethnicities, habits and customs in the Diamare plain. For example, in the locality of Mindif in Mayo-Kani division, ritual use was more important than that of Diamare division whereas human traditional pharmacopoeia and magic were similar in all the localities. Considering the knowledge of Loranthaceae according to age classes, the persons aged between 41-60 and 61 and more were holders of all uses of Loranthaceae ( Figure 3). Individuals included between 20 and 40 ages did not master all the uses of these hemiparasites, namely the ritual use. In fact, they are not involved in the receipts based on mistletoes. There was a significant difference between the tranches of ages (ANOVA, p ≤ 0.05).

Knowledge of Loranthaceae by ethnic groups in Diamare plain
In the Diamare plain, Loranthaceae are named according to the host species and each ethnic group has his own designation ( Table 1). The various designations are also in relation with the capacity of destruction of the Loranthaceae species. Seven (07) ethnic groups were identified in the study site, namely Toupouri, Moundang, Guiziga, Massa, Moufou, Peuhl and Sirata.    The preponderance of medicinal uses of Loranthaceae revealed by our investigations is well recognized around the world (Takem et al., 2014) and can be explained by the active ingredients contained in these hemiparasites. Among the diseases treated with Loranthaceae species, malaria, blood pressure and sterility were regularly cited. The use of Loranthaceae in the treatment of some of these diseases had already been reported (Dibong et al., 2009)  Knowledge of Loranthaceae was influenced by the age of respondents. Our results showed that people over 41 years old constituted the major poles of possession of knowledge of uses of Loranthaceae and must therefore be taken into account in priority in the different strategies for valuing these hemiparasites. and Tapinanthus globiferus represented 69.42% of the total rate of parasitism in natural sites and agrosystems. It could be seen that these two species are not specific to a host plant or a locality. Host species like Mangifera indica and Calotropis procera were widely cited by local populations because of the important role of the mistletoes they could host. But in the field, only one individual of Calotropis procera was attacked by Tapinanthus globiferus and no individual of Mangifera indica was parasitized. It could be observed that Calotropis procera is not very sensitive to hemiparasites and Mangifera indica is resistant to parasitic plants. Calotropis procera was found among the least sensitive host species in Benin  and Mangifera indica was said to be resistant to parasitic plants (Dibong et al., 2008). These results corroborate those of Dibong et al. (2008) which presented Mangifera indica as a resistant species to the parasitism of Loranthaceae and differ from those of Feguem (2011) and Amon et al. (2015). These authors showed that Mangifera indica was parasitized in the North-West region of Cameroon and South-Comoé region of Ivory-Coast respectively. These results make us think that to date, there are certainly no resistant species to hemiparasites, but rather species not yet discovered not parasitized by Loranthaceae species.

Conclusion
Ethnobotanical survey, carried out in Diamare plain of the sudano-sahelian zone of Cameroon, showed that nine Loranthaceae species were used by local populations. They were involved in five categories of uses, namely human traditional pharmacopoeia, veterinary medicine, fodder, ritual and mystical uses. Human traditional pharmacopoeia (96.92%) and magical use (82.30%) were the most important categories of uses. All the seven ethnic groups censused in the study site knew perfectly Loranthaceae species and persons aged above 41 years old were holders of all uses of these parasitic plants. The