by Schalk Schoeman

Mango bark beetle (Hypocryphalus mangiferae)

• Involved with tree mortalities in Malelane and possibly Pongola areas
• May transmit mango wilt Ceratocystis manginecans
• First noticed July 2019
• Farmers sprayed and destroyed dead and moribund trees
• So far no recurrence have happened

Bark borers

• Numbers appear to be increasing but not the pshb
• Sent various samples to FABI
• Probably related to plant stress, drought, heat
• Macadamia researchers in Hawaii and Australia made similar observations
• Need a country wide surveillance
• General lure will work but will attract all beetles – molecular techniques are quite expensive
• Will probably go into a wetter phase and suspect beetle problems to decrease

Tomato semi-looper (Chrysodeixis acuta)

Banana bunchy top virus and Pentalonia nigronervosa

• Colonies at base of plants under old leaf sheaths
• Move upwards when population increases
• Banana handbook mention chlorpyrifos
• * Imidachloprid injections used for aphid control
• Possibility of using entomopathogenic fungus for control of colonies

Banana slug

• Main issue is the change in the method how residue samples are taken.
• Wholesalers are picking up residues of slug pellets

False codling moth & Avocados

Damage

• Definite preference for certain cultivars – Pinkerton & Maluma Hass
• Easy to find on Maluma in Hazyview & Tzaneen
• Damage in Hazyview ± 20%
• Appears to facilitate infection of Anthracnose – needs scientific verification
• Damage in Africa (Tanzania & Northern Mozambique) in certain untreated areas more than 50%
• Damage potential of this pest is big because it is able to adapt to a new diet
• Cannot currently complete its life cycle in hard avocados but may do so in future – market access

Thrips in avocados and macadamias

Damage

• Is becoming a serious issue where macadamias and avocados are cultivated in close proximity.

• Cosmetic damage in avocados – fruit not fit for export
• Effect on following crop size on Smaller leaves – reduced photosynthetic area

• Pruning is central to effective spray Thrips normally severely affect new growth.
• Suspect resistance – not scientifically proven
• Dry hot summers – quicker generation time
• Warmer climate induce trees to flower out of sync – continuous availability of flowers and new flush

Macadamia felted coccid

(Update)

• ave located parasitoids – very low numbers
• Secondary sites now beginning to become infected
• Very heterogeneous distribution
• Definite cultivar preference
• Insects prolific during autumn & winter
• IGR + oil seemed to work very well – not registered

Immediate problems facing the subtropical fruit industry

• Thrips is an overarching problem and appears to become exponentially more Products are not working – resistance, poor application of pesticides or climatic?
• False codling moth is becoming a very serious problem for Maluma It is already a serious problem in Africa and may even in future become a quarantine issue
• Urgent need for the registration of Imidachloprid on bananas
• Need for the registration of Attract and Kill or Attract and Infect type products for the tomato semi-looper on bananas
• Are there alternative for slug bait in bananas?
• Need for registration of products against the macadamia felted coccid
• Need for a chemical with a knock down action that can be used for stink bug monitoring in lieu of dichlorvos