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© ICFR 2014 ICFR Limpopo Field Day

ICFR Limpopo Field Day Date: Tuesday 4 March 2014 Venue: Hanglip Arboretum Hall at KLF’s Hanglip Plantation, Louis Trichardt area GPS: S 23°0’34.9”; E 29°54’6.2” Time: 08h30 for 09h00

Programme

Time Topic Speaker

Indoor Presentations 08h30-09h00 TEA & COFFEE 09h00 Welcome Prof Colin Dyer, ICFR 09h10-12h00 Research challenges and opportunities facing the Industry Dr Andrew Morris, ICFR

Climate change and forestry in South Africa: Challenges and opportunities

Dr Ilaria Germishuizen, ICFR

Plantation forestry diseases - Lessons from history: It is time...

Prof Jolanda Roux, FABI

Puccinia psidii (Eucalypt rust) spatial risk model Dr Ilaria Germishuizen,

ICFR Update on biological control of plantation forestry pests in South Africa

Prof Jolanda Roux, FABI

12h00-12h30 LUNCH 12h30-15h30 Overview of Industry collaborative research on Fusarium

circinatum Dr Marnie Light, ICFR

Late rotation fertilisation of eucalypt sawtimber stands Dr Louis Titshall, ICFR Research at the ICFR to develop planting guidelines Dr Marnie Light, ICFR Update from the SA Sirex Control Programme including the National Monitoring data 2012/2013

Philip Croft

Field Stops 15h30-17h30 Visit and demonstrations for Sirex inoculations Philip Croft/Tim Ross/

Denzil Lawrie, SASCP Possible visits to Industry sites – Merensky/ KLF/ Molozi trust/ SLM


Research challenges and opportunities facing the in dustry

Andrew Morris

[email protected]

Institute for Commercial Forestry Research, PO Box 100281, Scottsville, Pietermaritzburg, 3209

Summary

Over the next ten years, plantation forestry in South Africa will see as much change as it has over the past fifty. Timber yields need to continue to increase, the risk of crop loss must be reduced and the wood produced must be acceptable to various markets. Forest management decisions will need up-to-date and ever more technical information. In this landscape, the ICFR aims to conduct relevant research able to support changing needs in the industry. This presentation will argue that opportunities for further yield improvements are real, can be sustainable and wood production can remain profitable. In support of this, the ICFR has various research projects covering three broad areas.

1. Efficient inter-rotation management Inter-rotation management is the period including felling and re-establishment up to canopy closure. The various activities involved in inter-rotation management account for the large part of operational costs and effectively determine the yield potential of the new crop. Containing the current cost of these activities whilst also realising the yield potential of the next crop is critical to the future of the industry. 2. Sustained production over multiple rotations The area of plantation forests in South Africa increased fairly steadily through the last century but has little changed for nearly two decades. The vast majority of plantations are now supporting at least the second crop and substantial areas are under third, fourth and even later rotations. Sustained production over multiple rotations is now not an academic debate but a practical necessity. Maintaining the production potential of the site, particularly nutrient supply and soil physical potential is vital. The spectrum of pests, pathogens and weeds also increases with each rotation and must be managed.

3. Good quality planting stock Good quality planting stock that is bred to improve yield, matched to site so as to mitigate risk (pests, diseases, frost, snow and drought), and provide wood acceptable to various markets is vital to any successful plantation. The ICFR is entirely responsible for supplying improved wattle seed to the industry and is also involved in supply of improved seed of various temperate eucalypts. The various presentations and field visits today showcase some of the valuable contribution that ICFR research is making to the future of our industry.


Climate change and forestry in South Africa: Challe nges and opportunities

Ilaria Germishuizen

[email protected] Institute for Commercial Forestry Research, P.O. Box 100281, Scottsville, Pietermaritzburg, 3209

Summary

Global predictions for the next 50 to 100 years foresee an increase in temperature, increase or decrease in rainfall, and an increase in the frequency and intensity of extreme events such as wind, fire and drought. Most of the climate change research in relation to forests has, up to now, dealt mainly with the role of forests in mitigating climate change, natural forest monitoring, and predicting changes in natural forests composition, whilst very little attention has been given to the effects of climate change on plantation forestry. Although there has been a big effort to develop climate change models at the regional scale for southern Africa, this information is not readily available in an easy-to-use format. As a response to the need for ready-to-use data by the South African forestry industry, the Institute for Commercial Forestry Research (ICFR) has initiated research projects and collaborations to bridge the gap between climatologists and foresters by applying climate change predictions to systems and models already in use for decision-making. This presentation gives an overview of the research and activities in the area of climate change currently ongoing at the ICFR. 1. Site classification and site-species matching A site classification system was developed by the ICFR as a platform for research planning, interpretation and uptake (Smith et al., 2005). This site classification is based on climate and lithology. The first level of classification is mean annual temperature (MAT) and the second level is mean annual precipitation (MAP), with a total of 27 site classes. Each site class is further characterised according to geological grouping. Medium and long term MAP and MAT climate change grids were used to develop a “future” site classification to interpret current research findings in future climate scenarios. Site class distribution is expected to shift towards warmer and moister sites in most areas (Figure 1).

Figure 1. Current and predicted rainfall classes distribution in commercial forestry areas.

28

29

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31

32

33

34

35

36

Dry Moist Wet

%

Current (1971-1990)

Intermediate (2046-2065)

Future (2081-2100)


An example of how a "future" site classification can assist in evaluating the impact of climate change on forestry is provided by linking "future" site classes to site-species matching. The medium and long term "future" site classifications were used to map changes in site-species suitability for the main commercially grown species and to identify changes in species importance. Results show that some species and hybrids could become more prominent in the forestry landscape, and highlight that resistance to certain pest and diseases and drought, and general species robustness are highly desirable traits in a changing environment. The predicted site-species suitability maps are useful tools for determining priorities in future tree improvement research and germplasm conservation. 2. Is climate change happening? A close look at wea ther trends in the South African forestry areas: 1950-2010 One hundred and thirty rainfall and temperature stations located in proximity of forestry areas and for which daily data was available were selected for this study. Changes in climate patterns were analysed by comparing two data subsets; 1950-1970 and 1987-2010. The parameters included to detect change are: mean annual precipitation (MAP), number of rainy days per year (Figure 2), number of rainy days >= 40 mm per year, monthly rainfall, average drier season rainfall, mean annual temperature (MAT), mean maximum temperature, mean minimum temperature, average number of “hot” days per year and average number of “cold” days per year. Results showed a general trend of increased rainfall variability from year to year, particularly during the drier months, and a decrease in number of rainy days per year. Temperature has also increased and become more variable and “hot” days, where temperature was equal or in excess of 300C, were more frequent. This simple analysis has confirmed perceptions of foresters on the ground and has highlighted the need to review common practices such as regional planting windows and revaluate seasonal fire and drought risks.

Figure 2. Average number of rainy days/year. Letters on bars indicate significance at p<0.05. 3. Partnerships, initiatives and collaborations The ICFR is involved in a number of collaborative initiatives and research projects with other research institutions. The main focus of these collaborations is around measuring the potential impact on various land uses, including forestry, and developing expertise in the area of climate change.

Rainy days 1950-1970 Rainy days 1987-2010


Conclusions Global predictions for southern Africa indicate an increase in MAT and MAP and more erratic climate patterns. The empirical analysis of weather trends in the forestry areas of South Africa for the period 1950-2007 shows that warmer temperatures and more erratic rainfall patterns are already a reality in the areas currently under forestry; however, foresters have not adapted their modus operandi to the change. Spatial modelling based on outsourced regional climate change predictions has proven to be successful in developing tools for the interpretation of forestry research findings in future climate scenarios.

References Smith CW, Pallett RN, Kunz RP, Gardner RAW and du Plessis M. 2005. A strategic forestry site

classification for the summer rainfall region of southern Africa based on climate, geology and soils. ICFR Bulletin Series 03/2005. Institute for Commercial Forestry, Pietermaritzburg, South Africa.


Plantation forestry diseases - Lessons from history : It is time...

Jolanda Roux

[email protected] Tree Protection Co-operative Programme (TPCP) and DST/NRF Centre of Excellence in Tree Health Biotechnology

(CHTB), Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria

Summary

Over the past century the number of pest and disease problems of plantation grown, non-native tree species, such as Acacia, Eucalyptus and Pinus, have grown exponentially (Figure 1). This phenomenon has been ascribed to increased international travel and trade and an associated increase in the movements of pests and pathogens with tree and timber products. At the same time, as non-native hosts have been exposed to microbes and insects in their new countries, increasing numbers of these microbes and insects have adapted to the non-native hosts, often resulting in disease and death of these trees.

In the past decade the South African forestry industry has seen an increasing number of pest problems appear on Eucalyptus species in the country. Since 2003, five new insect pests have been recorded on eucalypts in South Africa, of which four - Thaumastocoris peregrinus, Leptocybe invasa, Blastopsylla occidentalis and Glycaspis brimblecombei - are non-native species. The “cossid moth”, Coryphodema tristis, represents a possible native insect that has adapted to infect non-native Eucalyptus trees in South Africa. Over the past ten years, no new fungal diseases have been observed affecting plantation forestry tree species in South Africa. In May 2013, however, the Myrtle rust pathogen, Puccinia psidii, was observed in South Africa for the first time. Although not yet reported affecting plantation grown eucalypts in South Africa (Figures 2A and 2B), it is only a matter of time before this occurs. Early this year (2014), a new disease of Acacia mearnsii was reported by farmers in the KwaZulu-Natal Midlands (Figure 2C). The cause of this disease has been identified as a rust fungus, which is currently being identified.


Lessons from history have shown us that we can expect other pest and disease problems appearing on plantation grown trees in South Africa in the future. We, therefore, need to be continuously vigilant. Through sound management strategies, the impacts of these pests and pathogens can be limited to ensure sustainable and profitable plantation forestry. This will, however, only be possible through the involvement of all stakeholders, including forestry companies, farmers, government and scientists. Early detection and rapid, where possible pro-active, response in combination with sound forestry practices, tree breeding and new technologies are key to reducing the impacts of these tree health problems.

We encourage you to contact the research teams of the TPCP and CTHB at FABI, University of Pretoria, if you suspect any new disease or pest problems in your area. Jolanda Roux – 0829093202; [email protected] Izette Greyling – 0832691983; [email protected] Also, please join the email list server “treehealthnet” for regular updates on tree health issues, field visits to your area, and other forestry news. Please contact [email protected] to join the list server, or any other team member of the TPCP and CTHB research teams.


Puccinia psidii (Eucalypt rust) spatial risk model

Ilaria Germishuizen


Summary

The pathogen Puccinia psidii was first detected in South Africa in May 2013 on the KwaZulu-Natal South Coast. This pathogen represents a potential serious threat to Eucalyptus plantations and to native species of the family Myrtaceae, causing a rust disease. This presentation focuses on the development of a risk map to identify areas where the conditions required for the establishment of a viable population of P. psidii in South Africa are met, and it is part of a collaborative research project led by Prof Jolanda Roux (FABI), involving the ICFR (Dr Ilaria Germishuizen and Dr Ryan Nadel) and the Department of Agriculture, Forestry and Fisheries (DAFF) of Australia (Dr Geoff Pegg). The risk model uses bioclimatic variables as predictors to geographically map the potential distribution of P. psidii. Climatic variables and thresholds were defined based on available literature describing the climatic requirements of the pathogen in areas where viable populations could become established, particularly South America and Australia. Variable predictors selected for the model are average Relative Humidity (RH) and average Minimum Temperature (Tmin). Seasonal and annual risk maps were developed showing areas of potential high (RH ≥ 80% and Tmin ≥18 and ≤22 °C) and medium (RH ≥70% and Tmin ≥10 °C) risk ( Figure 1). The potential risk to Eucalyptus plantations was evaluated by overlaying the current areas under forestry to the potential geographic range of P. psidii. Most of the areas currently under forestry (about 80%) are within the geographic range suitable to P. psidii, indicating a potential threat to the health of Eucalyptus plantations in South Africa. The current distribution range of the four native species of the family Myrtaceae also broadly overlay with P. psidii suitable range, suggesting a potential threat to the regional biodiversity asset.


Figure 1. Potential Puccinia psidii high (RH ≥ 80% and Tmin ≥18 and ≤22 °C) and medium (RH ≥70% and Tmin ≥10 °C) risk areas in South Africa.

References Blum LEB, Dianese JC. 2001. Patterns of urediniospores release and development of rose apple rust.

Pesquisa Agropecuaria Brasileira 36: 845–850.

Booth TH, Old KM, Jovanovic T. 2000. A preliminary assessment of high risk areas for Puccinia psidii (Eucalyptus rust) in the Neotropics and Australia. Agriculture Ecosystems & Environment 82: 295–301

Glen M, Alfenas AC, Zauza EAV, Wingfield MJ, Mohammed C. 2007. Puccinia psidii: a threat to the Australian environment and economy – a review. Australasian Plant Pathology 36: 1-16.

Kriticos JD, Morin L, Leriche A, Anderson RC, Caley P. 2013. Combining a climatic niche model of an invasive fungus with its host species distributions to identify risks to natural assets: Puccinia psidii sensu latu in Australia. Plos 8(5): 13pp

Ruiz RAR, Alfenas AC, Ferreira FA. 1989. Effect of temperature, light and inoculum source on teliospore and urediniospore production of Puccinia psidii. Fitopatologia Brasileira 14: 70–73

Schulze RE. 2007. South African atlas of climatology and agrohydrology. Water Research Commission, Pretoria, RSA, WRC Report 1489/1/06


Update on biological control of plantation forestry pests in South Africa

Jolanda Roux

(on behalf of TPCP Biological Control Team)

[email protected] [email protected]

Tree Protection Co-operative Programme (TPCP), Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria

Summary

The plantation forestry industry in South Africa has experienced significant losses as a result of insect pest infestations of commercial plantations. These insects include both native and non-native insects. In some cases, such as with Sirex noctilio infestation, cumulative mortality of more than 50% of compartments was experienced at the height of infestations. Some of the main insect pests currently of concern are: Acacia mearnsii Eucalypt species Pinus species Kotochalia junodi (Bagworm) Lygidolon laevigatum (mirid)

Coryphodema tristis Glycaspis brimblecombei Gonipterus species Leptocybe invasa Thaumastocoris peregrinus

Euproctis terminalis (Brown tail moth) Imbrasia cytherea (Emperor moth) Sirex noctilio

The TPCP has been conducting extensive research on the use of biological control agents for the various forestry pests in South Africa. These biological control agents can be used in combination with breeding and selection, to reduce the impact of insect pests in plantations. The TPCP is currently actively involved in the rearing and release of biological control agents against Sirex noctilio (since 2004), Leptocybe invasa (since 2012) and Thaumastocoris peregrinus (since 2013), as well as the post-release monitoring of these agents in collaboration with the South African Sirex Control Programme, ICFR and TPCP members. Laboratory trials are underway with Psyllaephagus bliteus, a biological control agent of the red gum lerp psyllid, Glycaspis brimblecombei. A rearing system for P. bliteus has been optimised and host specificity trials will start later this year to assess its suitability for release in South Africa. At the same time, various Eucalyptus genotypes will be screened for their tolerance to G. brimblecombei. The TPCP is also investigating the potential use of entomopathogenic nematodes (EPNs) against establishment pests such as white grubs and cut worms. These pests have generally been controlled by the use of insecticides, but increasingly strict regulations and high costs of insecticide application will potentially restrict the use of this method in the future and having alternative methods for control will be crucial to avoid substantial losses. Although this work is still at an early stage, substantial progress has been made to rear different strains of EPNs and screening of these EPNs against the target insects will start this year. The native insect pest, Coryphodema tristis (cossid moth), was in 2014 detected in the KwaZulu-Natal Midlands. This is the first report of this pest of E. nitens, outside of the Lothair/Carolina region of South Africa. Great success has, fortunately, been achieved with the development of a pheromone lure to trap cossid moths. This lure, the result of many years of research, is currently being optimised for field use.


We encourage you to contact the entomology research team of the TPCP and CTHB at FABI, University of Pretoria, if you have any questions regarding insect pests and biological control. Brett Hurley – 012 4203938/9; [email protected] Jeff Garnas – 012 4203938/9; [email protected] Also, please join the email list server “treehealthnet” for regular updates on tree health issues, field visits to your area, and other forestry news. Please contact [email protected] to join the list server, or any other team member of the TPCP and CTHB research teams.


Overview of Industry collaborative research on Fusarium circinatum

Marnie Light1, Ryan Nadel, Andrew Morris, Nicky Jones, Craig Ford,

Izette Greyling, Gerda Fourie and Mike Kruger

[email protected]

Institute for Commercial Forestry Research, P.O. Box 100281, Scottsville, Pietermaritzburg, 3209

Summary

The major impact of Fusarium circinatum on the establishment and survival of Pinus patula has resulted in a collaborative effort by various industry and academic partners through several research projects. This presentation highlights some of these studies, conducted under the auspices of the South African Pitch Canker Control Programme and the Pine Fusarium Working Group. In particular, some of the pertinent results from two studies on the effect of spore load and stress in the nursery and its effect on field performance will be discussed, along with some results from two studies on seedling tray sanitation and culling (‘rogueing’) of symptomatic seedlings. Preliminary results from an additional study implemented in 2012 to develop a ‘seedling performance test’, for evaluating nursery performance in terms of F. circinatum infection in P. patula, will also be presented. Main findings from these trials have shown that the inoculation of P. patula seedlings with F. circinatum had the greatest impact on field survival. One study indicated that it is possible for asymptomatic seedlings to have an infection rate of >90%, although mortality was only observed after planting in field. Trials investigating the role of tray sanitation and the frequency of culling in the nursery revealed that sterilising trays significantly reduced both the nursery and post-planting mortality. Furthermore, regular (i.e. weekly) culling had a significant effect in reducing post-planting mortality, in comparison with infrequent (monthly) culling. Thus, high standards of operation are required to eliminate both primary and secondary infection from F. circinatum in the nursery.


Late rotation fertilisation of eucalypt sawtimber s tands

Louis Titshall


Summary

Post-thinning fertilisation of sawtimber stands is an approach that may increase final timber volume, reduce rotation length and reduce the time to recover returns from the cost of fertilisation. However, there is almost no literature on the response of eucalypt sawtimber stands to post-thinning fertilisation in South Africa. This study investigated the response to fertilisation after a second thinning operation of three Eucalyptus grandis sawtimber stands (HMS 1, 2 and 3) planted across a productivity gradient in Tzaneen. Three treatments were used that included a control (no fertiliser), NPK (nitrogen, phosphorus and potassium) and NPK+ (NPK with additional calcium, magnesium, copper, zinc and boron). Fertiliser was applied at non-limiting rates after the stands had undergone a second thinning operation. Growth data to 43 months after fertilisation are reported here. Sites HMS 1 and 3 had non-significant, but positive growth gains in the fertilised treatments relative to the control treatments. In the case of HMS 1, this was attributed to differences in initial tree size between plots and the loss of some trees in the control treatment. At HMS 3, the most productive site, there were non-significant divergent growth responses for the fertilised treatments relative to the control, suggesting a positive response to fertilisation. At HMS 2 the growth responses were small. A basic cost-benefit analysis indicated that there was no economic benefit to post-thinning fertilisation at this time.


Research at the ICFR to develop planting guidelines

Marnie Light


Summary

In plantation forestry it is imperative to obtain a well-established stand of trees in order to gain the maximum possible yield at rotation end. Such optimal stand establishment requires the successful transplanting of seedlings or cuttings in the field for maximum survival and suitable stocking. For several years, the Re-establishment Research Programme at the ICFR has conducted numerous research trials that have provided information pertinent to improving silvicultural operations related to re-establishment practices. This presentation provides a summary of some of the pine and eucalypt regeneration research findings, touching on aspects of seedling quality, pit preparation, application of water or hydrogel at planting, and the importance of using suitable planting techniques.


Update from the SA Sirex Control Programme includin g the National Monitoring data 2012 / 2013

Philip Croft


Summary

The Spread of Sirex noctilio in South Africa Since first being detected in South Africa in 1994, the woodwasp Sirex noctilio has spread across most of the country, and is currently one of the most serious invasive pests threatening the South African commercial pine plantations. Through the efforts and actions of the South African Sirex Control Programme (SASCP), this risk has been substantially reduced through timely and proactive monitoring and deployment of biological control agents. This presentation will discuss some of the key elements of the SASCP operations. Sirex infested tree identification The first aspect is the identification of a Sirex infested tree. During the wasp flight season, the female wasps lay eggs in pine trees that show signs of moisture stress, by inserting her ovipositor through the bark and cambium layer into the timber. She will lay one egg and then partially withdraw her ovipositor and drill a second tunnel off to one side and lay another egg at the end of the tunnel. This will take place until four to five eggs are laid at the end of each tunnel, and the last tunnel will have only fungus deposited into it. She then withdraws her ovipositor completely. Resin from the tree will close up the tunnels and form a droplet on the bark. Mucus is also secreted during the egg laying process and will translocate to the needles where desiccation occurs. The fungus reproduces in the stem preventing the uptake of water from the roots and supplies food for Sirex larvae. In effect the tree starts to dry out and the moisture under the bark of a Sirex infested tree is absent. Sirex females only live for a few days off body fat, and once the last egg is laid, she dies.

Signs indicating a Sirex-infested tree are visible from February to May in the summer rainfall areas, include brown needles, resin droplets on the bark and dry timber when the bark is removed. The evidence of a dead female wasp, or the remains of a female wasp, which is usually the abdomen and ovipositor, also provides good evidence proving the cause of tree mortality. To correctly assess a tree the brown crown + resin droplets + dry timber must all be present in one tree. The female wasp or abdomen rules out all other causes of tree mortality. To be 100% certain, the tree must be chopped into to find white larvae with a black spike at the rear end in a tunnel that is packed with white sawdust.

Deployment of biological control The nematode, Deladenus siricidicola of the Kamona strain is an effective biological means of controlling the Sirex noctilio wasp. These nematodes are mixed into stockosorb, a hydrogel, which acts as a carrying medium, stored in a plastic bottle. It is critical that the nematodes are kept at a temperature of between 5°C and 10°C prior to inoculation.

An inoculation hammer which has a round punch, is used to make holes into the tree in such a way that 50 holes are placed into a pine pulpwood tree (up to the age of 18 years) covering the area where the wasp has laid her eggs. The nematode and gel mixture is then inserted into these holes. The nematodes enter the Sirex larvae. When the larvae pupate into female wasps the nematodes enter the ovaries and disrupt the development of the eggs. When these eggs are laid, nematodes are transported to the following host tree where they become established.


Another biological control agent, Ibalia leucospoides wasps has been released in Tzaneen and Louis Trichardt areas of Limpopo. Four Ibalia were found in the emergence cages last year indicating their establishment in the KLF Hanglip area.

Parasitism results Parasitism, usually expressed as a percentage, is the number of Sirex wasps that are carrying either nematodes in eggs (female wasps) or in the testis (male wasps). To measure the parasitism rate, emergence cages housing Sirex-infested logs are used. The wasps are caught and dissected to determine if the nematode is present or not. Currently, there are three depots with a total of 1000 cages with timber from all pine regions of South Africa. Each cage is numbered and recorded with the origin of the logs. With this method we are able to measure parasitism across the country, and determine if the levels are sufficient to control the wasp population. Parasitism measurement is linked to the number of dying trees to give a more complete indication of control.

National Monitoring Results; 2012 and 2013 The Programme has implemented a National Monitoring initiative in the form of plots laid out across the mature pine landscape, set up to measure the number of dying and dead trees resulting from Sirex activity. A plot is a line transect 75 metres long repeated three times or until a total of 75 trees have been recorded. Monitoring is done annually to determine trends over time. The number of transects depends on the stems per hectare which varies between pulpwood and saw timber regimes.

Presently, the Programme has 535 monitoring plots across the country, which have been measured over two successive years.

National monitoring and emergence cage parasitism National monitoring measures the severity of tree mortality and parasitism indicates the level of biological control that has been established.

As indicated in the Table above, all the regions except for the Central region and Mpumalanga Limpopo have good parasitism and low tree mortality. The Central region has some higher tree mortality which is

DA

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Par

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sm

Pop

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ion

Ibal

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Par

asiti

sm

Prio

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Region Low High Overall Sirex per Log Dead DyingW Cape 1 3 0.0% 0.0% 4S Cape 1 3 22% 4.9 32% 1.1% 0.3% 4E Cape (2012) 1 2 45% 5.9 20% 1.1% 0.1% 5KZN 1 4 49% 5.3 42% 0.1% 0.4% 5S Mpumalanga 1 3 9% 26.7 0.3% 1.1% 1.5% 1N Mpumalanga 1 3 18% 10.9 0.0% 0.2% 0.3% 3Limpopo 1 2 8% 23.5 0.3% 0.0% 0.0% 2

Risk Rating1 Low 3 High2 Moderate 4 Very High

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Emergence cagesClimate Nat. Mon


of concern. This area was inoculated again in 2013. Inoculation is like weed control and follow-up is necessary to obtain the desired results.

In the war against Sirex noctilio, we know that pine trees do not defend themselves, and stressed pine trees attract Sirex females. The nematodes actively seek out Sirex larvae, infesting the eggs, and being transported to the next tree, when the female lays her eggs. Perceptions can be changed by the results presented from the national monitoring and parasitism data, which show that Sirex is losing the battle!!!

A success story for forestry!!!

icfr limpopo field dayicfr limpopo field day tuesday 4 march 2014 venue: hanglip arboretum hall at...

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