Agriculture

5. 1(a) PSHB has been detected in all provinces accept for Limpopo and is present in most major cities. In the Western Cape, major infestations occurs along the Garden Route, Somerset West, the Southern Suburbs of Cape Town and around Stellenbosch.  Hortgro is currently following up on unconfirmed PSBH symptoms and trap catches in other parts of the Province.

(b) The Forestry and Agriculture Biotechnology Institute (FABI) at the University of Pretoria has a national map at https://www.fabinet.up.ac.za/pdf/PSHB/7-PSHB%20distribution%20map%202021-03-04.pdf.  It must also be  noted that the map has last been updated during  March 2021. HORTGRO has a map at https://pshb.hortgro.science/monitoring/monitoring-detection-and-distribution/ and is monitoring for PSHB in deciduous fruit production regions – see below. The trapping grid for 2023/2024 has been expanded to include Piketberg, the Koue Bokkeveld and additional parts of the Klein Karoo.

(2) Despite ongoing research by FABI and HORTGRO, little progress has been made in the identification of effective chemical treatments.  While some chemical treatments, when regularly injected into the trunk of trees, can reduce infestation, they do not seem to be curative on the long-run or feasible for use by commercial agriculture. Concerted efforts by researchers and arborists at Disney World California, have shown that a holistic approach to beetle infestation including regular monitoring, removing of reproductive hosts and infested branches, spot treatment with chemicals and good sanitation practices can be successful to protect high-value ornamental trees. It is, however, a very intensive and costly approach and less suitable/feasible in a commercial agricultural set-up. Biological control agents including entomopathogenic fungi and parasitoids (from the native range) are being explored for use as part of PSHB management.

(3) (a) A pear orchard in Somerset West was the first commercial fruit in the Western Cape to be infested by PSHB. Plum and apple orchards on the same farm have subsequently been infested (low levels).  Pears have since been established to be a reproductive host of PSHB. Pathogenicity studies and observations in home gardens suggest that other deciduous crops like apple, peach/nectarine, plum, apricot and cherry may also be hosts.  PSHB attacks the trunks of these trees, which makes it more difficult to control. In the case of pecan nuts and avocados, which are also hosts, PSHB attacks branches. PSHB management in these crops involve the removal of infested branches.

(b) PSHB poses a major threat to deciduous fruit farmers since there is currently no effective and feasible means of control. There is also no legislation in place to prevent the spread of PSHB or to force home and landowners to remove reproductive hosts that can serve as sources of the beetle. PSHB also poses a significant threat to agricultural tourism with the English oaks surrounding and contributing to the ambience at various tourist farms being a reproductive host and succumbing relatively quickly to infestation.

(4) The Western Cape Department of Agriculture is part of the Provincial Disaster Risk Committee where PSHB is also discussed, and also communicate on a regular basis with the National Disaster team and the Plant Health Early Warning Systems team residing at DALRRD.