Spelling suggestions: "subject:"Pests--Control--South africa."" "subject:"Pests--Control--South affrica.""
21 |
Insect pests of cultivated and wild olives, and some of their natural enemies, in the Eastern Cape, South AfricaMkize, Nolwazi January 2009 (has links)
This thesis has two focuses. The first problem facing the olive industry in the Eastern Cape is the growers’ perceptions of both what the industry will provide them and what a pest management program might entail. The second focus is the biology of olive pests in the Eastern Cape in terms of understanding their populations and their natural enemies on private farms, with future hopes of understanding how Integrated Pest Management strategies can be developed for this crop. Eastern Cape private farmers, small-scale farmers and workers from agricultural training institutions were interviewed regarding the history and cultivation of the local olive crop. Only one commercially viable olive grove was identified; other groves were small, experimental pilot ventures. The introduction of olives to small-scale farmers and agricultural training schools was generally a top-down initiative that led to a lack of sense of ownership and the trees being neglected. Other problems included poor human capital; poor financial capital; lack of adequate support; lack of knowledge transfer and stability; lack of communication and evaluation procedures of the project; miscommunication; and finally, olive pests. Apart from hesitancy to plant at a commercial scale, the main problem facing private farmers (Varnam Farm, Hewlands Farm and Springvale Farm) was pests. Therefore an investigation of pests from private farms was conducted ranging from collection of cultivated and wild olive fruit and flea beetle larvae for parasitism, trapping systems both for fruit flies and olive flea beetle adults. A survey of olive fruits yielded larval fruit flies of the families Tephritidae (Bactrocera oleae (Rossi), B. biguttula (Bezzi) and Ceratitis capitata (Wiedemann)) and Drosophilidae (Drosophila melanogaster (Meigen)) from wild olives (O. europaea cuspidata (Wall. ex G. Don) Cif.) but none from cultivated olives (O. e. europaea L.). Braconid wasps (Opiinae and Braconinae) were reared only from fruits containing B. oleae and B. biguttula. This suggests that B. oleae is not of economic significance in the Eastern Cape, perhaps because it is controlled to a significant level by natural enemies, but B. biguttula may be a potential economic pest. A survey of adult fruit flies using ChamP traps baited with ammonium bicarbonate and spiroketal capsules and Sensus trap baited with methyl eugenol and Questlure confirmed the relative importance of B. biguttula over B. oleae. ChamP traps were over 50 times better than Sensus traps for mass trapping of B. biguttula but both were ineffective for trapping B. oleae and C. capitata. Six indigenous flea beetles of the genus Argopistes Motschulsky (Chrysomelidae: Alticinae) were found, three described by Bryant in 1922 and 1944 and three new species. Their morphology was investigated by scanning electron microscopy and mutivariate morphometric analysis. The leaf-mining larvae are pests of wild and cultivated olives in South Africa and threaten the local olive industry. At Springvale Farm, A. oleae Bryant and A. sexvittatus Bryant preferred the upper parts of trees, near new leaves. Pseudophanomeris inopinatus (Blkb.) (Braconidae) was reared from 23 Argopistes larvae. The beetle larvae might not be controlled to a significant level by natural enemies because the rate of parasitism was low. The olive flea beetles showed no attraction to traps containing various volatile compounds as baits. The lace bug, Plerochila australis Distant (Tingidae), was sometimes a pest. It showed a preference for the underside of leaves on the lower parts of the trees. A moth, Palpita unionalis Hübner (Crambidae), was reared in very low numbers and without parasitoids. A twig-boring beetle larva, chalcidoid parasitoids and seed wasps of the families Eurytomidae, Ormyridae and Eupelmidae were also recorded.
|
22 |
The use of chlorpyrifos to control American bollworm (helicoverpa armigera) in oranges (citrus sinensis l.) in the Eastern Cape province of South AfricaSiyoko, Kotose Joseph 02 1900 (has links)
The objectives of this study were to establish the effectiveness of chlorpyrifos in suppressing H. armigera population in oranges and to determine the effect chlorpyrifos had on the health of farm pesticide operators. Experiments showed that by applying chlorpyrifos on orange trees, H. armigera larvae population was suppressed significantly. High fruit yields were realized from trees that were sprayed with chlorpyrifos.
Visual observation of personnel involved in pesticide related duties, revealed that judicious use of pesticides was not practiced by farm workers in all three farms. Data analysis from questionnaires, health records and interviews proved that farm workers suffered from illnesses that were pesticide related. It was mainly those farm workers in the age group of 31 to 35 years who suffered the most from pesticide related illnesses. / Agriculture and Life Sciences / M. Sc. (Agriculture)
|
23 |
Ecosystem services and disservices of ants in subsistence farming (Limpopo Province) : an experimental approach in mango orchards.Maphote, Vongani Terrence 18 August 2017 (has links)
MSc (Zoology) / Department of Zoology / See the attached abstract below
|
24 |
Studies on Sclerotinia sclerotiorum (Sclerotinia stem rot) on soybeans.Visser, Dael Desiree. January 2007 (has links)
Soybeans, Glycine max, are an economically and strategically important crop in South
Africa (SA). In order to meet local demands, large imports of soybeans are required,
e.g., in the 2005/2006 soybean production period, 842 107 tonnes of oilcake were
imported. Due to an increase in soybean production throughout the world, diseases that
affect this crop have also increased in incidence and severity.
Sclerotinia sclerotiorum, the causal organism of sclerotinia stem rot (SSR), is an
important yield limiting disease of soybeans, as well as numerous other crops. The
pathogen was first reported in SA in 1979. However, it was only in 2002 that this fungus
was considered a major pathogen of soybeans in SA.
The research reported in this thesis was conducted to investigate the epidemiology of
S. sclerotiorum and examine numerous potential control methods for this pathogen, i.e.,
resistant cultivars, biocontrol, chemical control and seed treatments. A S. sclerotiorum
isolate was obtained from sunflowers in Delmas, Mpumulanga, SA, in the form of
sclerotia. This isolate was cultured and sent for identification and deposition in the Plant
Protection Research Institute collection. This isolate, in the form of mycelia, was used
for the duration of the study.
For epidemiology studies, the effect of temperature, leaf wetness duration (LWD) and
relative humidity (RH) were examined for their effect on rate of pathogen development.
Twenty four combinations of temperature (19°C, 22°C, 25°C and 28°C), LWD (24, 48
and 72 hr) and RH (85 and 95%) were investigated. No interaction between
temperature, LWD and RH was found. Temperature alone was the only factor that
affected disease development. At 22°C, the rate of pathogen development (0.45 per
unit per day) was significantly higher than all other temperatures, indicating that this
temperature is optimum for disease development.
Thirteen different soybean cultivars, i.e., LS6626RR, LS6710RR, LS666RR, LS555RR,
LS6514RR, LS678RR, Prima 2000, Pan 626, AG5601RR, AG5409RR, 95B33, 95B53
and 96B01B, commercially grown in SA were investigated for their reaction to
S. sclerotiorum. Prima 2000, 96B01B, 95B33 and AG5409RR were considered to be
the least susceptible as they showed a significantly low rate of pathogen development
(0.28, 0.28, 0.24, 0.23 per unit per day, respectively) and produced a significantly low
number of sclerotia (3.03, 3.42, 3.21, 2.38, respectively). LS6626R and LS666RR may
be considered most susceptible because of their significantly high rate of pathogen
development (0.45 and 0.42 per unit per day, respectively) and high sclerotia production
(8.16 and 7.50, respectively). Regression analysis showed a positive correlation
coefficient (R2=0.71) between rate of growth of the pathogen and number of sclerotia
produced, indicating that a higher rate is associated with a higher number of sclerotia.
In vitro dual culture bioassays were performed to identify the biocontrol mechanisms of
the biocontrol agents, EcoT® (a seed treatment) and Eco77® (a foliar treatment), against
hyphae and sclerotia of S. sclerotiorum. Ultrastructural studies revealed that
mycoparasitism is the probable mode of action as initial signs of hyphae of EcoT® and
Eco77® coiling around hyphae of S. sclerotiorum were observed. Surface colonization
of sclerotia by hyphae of EcoT® and Eco77® was also observed.
In vitro antagonism of EcoT® against S. sclerotiorum on soybean seed was performed to
determine pre-emergence and post-emergence disease. There was no significant
difference in percentage germination between seeds treated with EcoT® and plated with
the pathogen, untreated seeds and no S. sclerotiorum, and the control (i.e. no EcoT®
and no pathogen). However, percentage non infected seedlings from seeds not treated
with EcoT® was significantly lower, suggesting that EcoT® may be successfully used as
a seed treatment for the control of SSR. In vivo trials were performed to investigate the
effect of silicon (Si) alone, and in combination with Eco77®, on the effect of the rate of
disease development. Plants treated with Eco77® had a significantly lower rate of
disease development (0.19 per unit per day for plants treated with Eco77® and S.
sclerotiorum and 0.20 per unit per day for plants treated with Eco77®, S. sclerotiorum
and Si), compared to plants not treated with Eco77® (0.29 per unit per day for plants
treated with S. sclerotiorum and 0.30 per unit per day for plants treated with S.
sclerotiorum and Si), regardless of the application of Si. Similarly, plants treated with
Eco77® had a significantly lower number of sclerotia (0.46 for plants treated with Eco77®
and S. sclerotiorum and 0.91 for plants treated with Eco77®, S. sclerotiorum and Si),
compared to plants not treated with Eco77® (3.31 for plants treated with S. sclerotiorum
and 3.64 for plants treated with S. sclerotiorum and Si). The significantly lower rate of
disease development coupled with a significant reduction in sclerotia showed that
Eco77®, and not Si, was responsible for reducing the severity of SSR. A strong positive
correlation between rate of disease development and the number of sclerotia produced
(R2=0.79) was observed.
For the investigation of various fungicides for the control of S. sclerotiorum, in vitro trials
to determine the potential of three different fungicides at different rates, i.e., BAS 516
04F (133 g a.i. ha-1), BAS 516 04F (266 g a.i. ha-1), BAS 512 06F (380 g a.i. ha-1) and
Sumisclex (760 g a.i. ha-1) were initially conducted. The control (non-amended PDA)
had a significantly higher area under mycelial growth curve (243.0) than all fungicides
tested. BAS 516 04F (at both concentrations) and BAS 512 06F completely inhibited
the mycelial growth of S. sclerotiorum. Sumisclex inhibited the fungus by 89.07%. For
in vivo trials, preventative treatments, i.e., BAS 516 04F (133 g a.i. ha-1), BAS 516 04F
(266 g a.i. ha-1), BAS 512 06F (380 g a.i. ha-1), curative treatment, i.e. Sumisclex (760 g
a.i. ha-1) and a combination preventative/curative treatment, i.e., BAS 512 06F (380 g
a.i. ha-1)/Sumisclex (570 g a.i. ha-1) were investigated. No significant difference in
disease severity index (DSI) was found between fungicide treatments and the inoculated
control. BAS 512 06F and BAS 512 06F/Sumisclex had significantly lower grain yields
(6.09 g and 5.96 g, respectively) compared to all other treatments. There was a positive
correlation coefficient (R2=0.76), between DSI and grain yield, indicating that a high DSI
is correlated with low grain yield.
Trials to evaluate the effect of commercially available and currently unregistered seed
treatments for the control of S. sclerotiorum on soybean seeds in vivo and in vitro were
performed. Seed germination tests were performed to determine if seed treatments had
any negative effects on seed germination in vitro. All seed treatments tested, i.e., BAS
516 03F (8, 16 and 32 ml a.i. 100 kg-1 seed), BAS 512 00F (7.5, 15 and 32 ml a.i. 100
kg-1 seed), Celest XL (100, 125, 200 and 250 ml a.i. 100 kg-1 seed), Sumisclex (5 and 10
ml a.i. 100 kg-1 seed), Benomyl (150 g a.i. 100 kg-1 seed), Captan (240 ml a.i. 100 kg-1
seed), Thiulin (180 g a.i. 100 kg-1 seed) and Anchor Red (300 ml a.i. 100 kg-1 seed),
showed no negative effect on seed germination. For in vivo trials, BAS 516 03F (16 and
32 ml a.i. 100 kg-1 seed), BAS 512 00F (7.5, 15 and 32 ml a.i. 100 kg-1 seed), Celest XL
(100, 125, 200 and 250 ml a.i. 100 kg-1 seed), Sumisclex (5 and 10 ml a.i. 100 kg-1
seed), Benomyl and Anchor Red had significantly similar percent germination and
percent seedling survival as the untreated/uninoculated control. These seed treatments
should be recommended for the control of S. sclerotiorum, as they protected seed
during germination and subsequent seedling development. BAS 516 03F (8 ml a.i. 100
kg-1 seed) should not be recommended for the control of SSR, as it gave the lowest
percent germination and percent seedling survival.
The results presented in this thesis have helped to identify optimal environmental
conditions for the development of S. sclerotiorum, which is important for the
development of forecasting models for disease control. The least and most susceptible
cultivars of those tested have been identified. Biocontrol using Eco77® as a foliar
application showed great potential.
The effect of Si needs to be further investigated, including the testing of more frequent
applications and higher concentrations. The fungicides tested in this research did not
show any potential for the control of SSR. However, the spray programme tested is for
the control of soybean rust (Phakopsora pachyrhizi), and was investigated for its
potential for the control of SSR. The spray programme, fungicide application and rating
scale needs to be modified, to determine the true potential of these fungicides for the
control of SSR. Numerous seed treatments have shown potential for the control of seed
infection by SSR. Due to difficulties in producing ascospores, which are the primary
source of inoculum for this pathogen in the field, all studies in this research were
conducted with mycelia and not ascospores. The production, collection and storage of
ascospores needs to be thoroughly investigated, and research conducted with
ascospores. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2007.
|
25 |
Towards the development of a mycoinsecticide to control white grubs (Coleoptera: Scarabaeidae) in South African sugarcaneGoble, Tarryn Anne January 2013 (has links)
In the KwaZulu-Natal (KZN) Midlands North region of South Africa, the importance and increased prevalence of endemic scarabaeids, particularly Hypopholis sommeri Burmeister and Schizonycha affinis Boheman (Coleoptera: Melolonthinae), as soil pests of sugarcane, and a need for their control was established. The development of a mycoinsecticide offers an environmentally friendly alternative to chemical insecticides. The identification of a diversity of white grub species, in two Scarabaeidae subfamilies, representing seven genera were collected in sugarcane as a pest complex. Hypopholis sommeri and S. affinis were the most prevalent species. The increased seasonal abundances, diversity and highly aggregated nature of these scarabaeid species in summer months, suggested that targeting and control strategies for these pests should be considered in this season. Increased rainfall, relative humidity and soil temperatures were linked to the increased occurrence of scarab adults and neonate grubs. Beauveria brongniartii (Saccardo) Petch epizootics were recorded at two sites in the KZN Midlands North on H. sommeri. Seventeen different fluorescently-labelled microsatellite PCR primers were used to target 78 isolates of Beauveria sp. DNA. Microsatellite data resolved two distinct clusters of Beauveria isolates which represented the Beauveria bassiana senso stricto (Balsamo) Vuillemin and B. brongniartii species groups. These groupings were supported by two gene regions, the nuclear ribosomal Internal Transcribed Spacer (ITS) and the nuclear B locus (Bloc) gene of which 23 exemplar Beauveria isolates were represented and sequenced. When microsatellite data were analysed, 26 haplotypes among 58 isolates of B. brongniartii were distinguished. Relatively low levels of genetic diversity were detected in B. brongniartii and isolates were shown to be closely related. There was no genetic differentiation between the two sites, Harden Heights and Canema in the KZN Midlands North. High gene flow from swarming H. sommeri beetles is the proposed mechanism for this lack of genetic differentiation between populations. Microsatellite analyses also showed that B. brongniartii conidia were being cycled from arboreal to subterranean habitats in the environment by H. sommeri beetles. This was the first record of this species of fungus causing epizootics on the larvae and adults of H. sommeri in South Africa. The virulence of 21 isolates of Beauveria brongniartii and two isolates of B. bassiana were evaluated against the adults and larvae of S. affinis and the adults of H. sommeri and Tenebrio molitor Linnaeus (Coleoptera: Tenebrionidae). Despite being closely-related, B. brongniartii isolates varied significantly in their virulence towards different hosts and highlighted the host specific nature of B. brongniartii towards S. affinis when compared to B. bassiana. Adults of S. affinis were significantly more susceptible to B. brongniartii isolates than the second (L2) or third instar (L3) grubs. The median lethal time (LT₅₀) of the most virulent B. brongniartii isolate (C13) against S. affinis adults was 7.8 days and probit analysis estimated a median lethal concentration (LC₅₀) of 4.4×10⁷ conidia/ml⁻¹. When L2 grubs were treated with a concentration of 1.0×10⁸ conidia/ml⁻¹, B. brongniartii isolates HHWG1, HHB39A and C17 caused mortality in L2 grubs within 18.4-19.8 days (LT₅₀). Beauveria brongniartii isolate HHWG1 was tested against the L3 grubs of S. affinis at four different concentrations. At the lowest concentration (1×10⁶ conidia/ml⁻¹), the LT₅₀ was 25.8 days, and at the highest concentration (1×10⁹ conidia/ml⁻¹) the LT₅₀ dropped to 15.1 days. The persistence of B. bassiana isolate 4222 formulated on rice and wheat bran and buried at eight field sites in the KZN Midlands North was evaluated by plating out a suspension of treated soil onto a selective medium. All eight field sites showed a significant decline in B. bassiana CFUs per gram of soil over time, with few conidia still present in the samples after a year. Greater declines in CFUs were observed at some sites but there were no significant differences observed in the persistence of conidia formulated on rice or wheat bran as carriers. Overall, poor persistence of B. bassiana isolate 4222 was attributed to suboptimum temperatures, rainfall, which rapidly degraded the nutritive carriers, attenuated fungal genotype and the action of antagonistic soil microbes. Growers’ perceptions of white grubs as pests and the feasibility of a mycoinsecticide market were evaluated by means of a semi-structured questionnaire. The study showed that the reduced feasibility of application, general lack of potential demand for a product, high cost factors and most importantly, the lack of pest perception, were factors which would negatively affect the adoption of a granular mycoinsecticide. Growers however exhibited a positive attitude towards mycoinsecticides, and showed all the relevant attributes for successful technology adoption. It is recommended that because B. brongniartii epizootics were recorded on target pests which indicated good host specificity, dispersal ability and persistence of the fungus in the intended environment of application; that a mycoinsecticide based on this fungal species be developed. What will likely increase adoption and success of a mycoinsecticide is collaboration between various industries partners to increases market potential in other crops such as Acacia mearnsii De Wild (Fabales: Fabaceae).
|
26 |
Ecology and management of bat communities to increase pest control in macadamia orchards, Limpopo , South AfricaWeier, Sina Monika 18 May 2019 (has links)
PhD (Zoology) / Department of Zoology / An ever growing human population and accelerating land use change is associated with the
loss of species and their ecosystem services. Agricultural intensification has led to a
worldwide threat of extinction to about one quarter of all bat species, despite the valuable
ecosystem service of pest control provided by bats. The decline in bat populations is
mainly attributed to the loss or fragmentation of habitats, roost sites and feeding
opportunities related to agricultural intensification and land use change. Therefore, proactive
management of bat communities in agricultural landscapes is essential. South Africa is the
world’s largest producer of macadamias and the industry continues to grow.
This study gains insight into the habitat use and foraging behaviour of insectivorous bat
species on a temporal and spatial scale, in and around macadamia orchards in order to
advise management strategies on how to increase bat activity and, possibly, pest control. It
also focuses on the preferences of artificial roost sites used by insectivorous bats in
macadamia orchards. The diet of insectivorous bat species is especially difficult to study and
the least invasive tool to gain information is the study of bat faecal pellets. In order to
provide evidence for the consumption of pest insect species by bats and thus incentive to
farmers for a more integrated pest management approach (IPM), this study explored
molecular approach to insectivorous bat diet analyses using fragment analysis of bat faecal
pellets with fluorescent-labelled species-specific primers (designed for the CO I gene).
This study was conducted in the subtropical fruit growing area of Levubu, Limpopo province,
South Africa between the towns Thohoyandou (22°59'03.7 S, 30°27'12.8 E) and
Makhado/Louis Trichardt (23°03'03.6 S, 29°55'12.7 E). Levubu also accounts for the second
highest production of macadamia in South Africa.
An introduction to the order Chiroptera and into the relevance of insectivorous bat species to
agriculture as well as the importance of a more integrated pest management approach (IPM)
focusing on bats is provided in Chapter One.
Bats were acoustically monitored and light traps were used to catch arthropods during one
annual cycle. I sampled five macadamia orchards once a month from September 2015 to
August 2016 and used GIS and R to analyse both the general bat activity and foraging bat
activity of the two main foraging guilds (open-air/clutter edge guild) in different land use
types as well as total bat activity with respect to arthropod abundances. As reported in
Chapter Two, results show that the overall clutter edge guild activity (number of passes)
decreased with macadamia and orchard (all other fruit) cover in the macadamia high season
(December to end of May) and increased with bush cover and distance to settlements
(potential roosts) in the macadamia low season (June to end of November). Open-air guild
activity increased with fallow cover (uncultivated grassland with scattered trees and shrubs)
in the high season. Foraging activity (feeding buzzes) of the clutter edge guild increased with
bush cover over the whole year. Total activity (both guilds) increased with abundance of true
bugs (Hemiptera), including the main macadamia pests, and bush cover. Macadamia cover
has a negative effect on the activity of the clutter edge guild in the high season, with low
activity in the orchard center (high cover), and activity increasing in a linear way with
decreasing orchard cover at the orchard edge (low cover).
These results suggest that the clutter edge guild prefers foraging close to the edges of the
orchards rather than in the center, while the open-air guild prefers semi-natural habitats
(fallow). When numbers of pest arthropods drop in the macadamia orchards, the natural
land use type, bush, becomes a more important foraging habitat and thereby increased the
activity of the clutter edge guild.
From June 2016 to July 2017, I scanned 31 bat houses, mounted on poles on six macadamia
orchards, for bats or any other occupants such as wasps, birds and bees. Twenty-one multichambered
bat houses of three slightly different chamber designs were erected on poles, in
sets of three. Additionally, five bat houses of the type ‘Rocket box’, four bat houses in sets of
two (black and white) and one colony bat house were erected. Bats were counted and visually
identified to family or species level. From December 2016 to end of March 2017, three IButtons
were installed to record temperature variation between one set of three bat houses. As reported in
Chapter Three, results show that the central bat house in the set of three and the black bat
house in the set of two had a significantly positive effect on bat house occupancy. There was
a significant difference in the mean temperature between the houses in the set of three,
with a significant difference in temperature of 0.46°C between the central and the first bat
house. The three bat houses erected in sets varied slightly in their chamber design, with the
central bathouse having the most chambers (six), while the bat houses to either side had less
chambers (four), set at an angle or straight. This and the insulation to either side by the
other bat houses is assumingly what caused the central bat house to be on average warmer.
The Yellow-bellied house bat (Scotophilus dinganii) was by far the most recorded and the
only species observed to co-habitat a bat house with another animal species, in particular
honeybees. The study might confirm assumptions in that the microclimate of bat houses,
respectively their insulation, sun exposure and color appear to be important factors
influencing bat house occupancy. The two preferred bat houses in our study were the black,
in the set of black and white, as well as the central, and on average warmest bat house, in the
set of three.
I collected bat faecal pellets with two different methods between July 2015 and April 2017
to determine the prevalence of pest insects in faecal pellets. Eighteen of the bat houses (in
sets of three) on three different farms and two Egyptian slit-faced bat (Nycteris thebaica)
roosts were fitted with trays in order to collect pellets from those occupied by bats. I noted
occupancy of bat houses to species or family level to keep disturbance minimal. Additionally,
I collected pellets from individuals captured by means of mist nets and harp traps. Four of
the main pest-insects; the two-spotted stinkbug (Pentatomidae: Bathycoelia distincta), the
green vegetable bug (Pentatomidae: Nezara viridula), the macadamia nut borer (Tortricidae:
Thaumatotibia batrachopa) and the litchi moth (Tortricidae: Cryptophlebia peltastica), were
collected from pheromone traps or after scouting for primer development and optimisation.
After extracting DNA from the bat faecal samples the target regions were amplified in a
multiplex PCR and fluorescently labelled PCR amplicons were analysed and interpreted. In
order to verify multiplex analyses results, all samples were amplified with all four sets of
primers in plates and those that produced amplicons were purified and sequenced. As
reported in Chapter Four, results show that fragment analyses yielded a total of 63 out of
103 samples tested positive for pest insect species (61%) with a total of 92 positive
fragments. Primer specificity could be confirmed to 100% for the sequences obtained for
Bathycoelia distincta (26/26) and Nezara viridula (12/12) primers but not for all sequences
obtained fot Cryptophlebia peltastica (18/30) and Thaumatotibia batrachopa (1/14) primers.
One sample showed no positive fragments but contained a positive sequence for N. viridula.
Three samples tested positive for one pest-species fragment but contained a positive
sequence for a second pest-species (B. distincta, T. batrachopa and C. peltastica). Adding
four positive fragments and one additional positive sequence to the data. This means that
sequences of pest insect species were obtained from 54 out of the 103 samples (55.6%) with
a total of 73 pest insect sequences. For the high season (December to end of May) a total of
37 positive fragments for the four pest insect species and 24 negative samples were yielded
and for the a low season (June to end of November) a total of 36 positive fragments and 15
negative samples. Looking at the pest consumption of the different bat species or families,
our results show that all of them foraged on pest insect species. Whereas, all species and
families except Myotis bocagii and Rhinolophus simulator (for which N<2) foraged on both
the Lepidopteran and Hemipteran pest species. Therefore, all families of bats of which faecal
pellets were analysed for this study (Molossidae, Nycteridae, Rhinolophidae and
Vespertilionidae) foraged on one or more of the four pest insect species.
In summary, Chapter Five concludes that natural and semi-natural vegetation promote bat
activity in macadamia orchards, and potentially bats' provision of the ecosystem service of
pest control. In times of accelerating land use change, remnants of natural vegetation are
important refuges and need to be maintained or restored to conserve bat species and
promote their ecosystem services. The study also shows that bat activity might be improved
by adding roosting opportunities to orchards. Warm and well-insulated bat houses mounted
freestanding on poles and in sets appeared to work best in northern South Africa. Further
research on co-habitation of bat houses and displacement behaviour as well as the potential
importance of altitude and distance to water is needed.
All of the species or families of bats from which faecal pellets were collected have been
confirmed to forage on at least one of the four pest insects and the bat species have shown
to be much more generalist and presumably opportunistic feeders than previously assumed.
Thus, this study provides incentive and advice to farmers for a more integrated pest
management approach (IPM). / NRF
|
Page generated in 0.0738 seconds