Page 68 - SA Fruit Journal VOLUME 14

EXTENSION BRIEFS FOR FEB & MARCH 2015H.F. lE rOux & J.J. BEStEr Citrus Research InternationalINTEGRATED PEST MANAGEMENT Mealybug S.D. MOOREGrowers should be scouting for mealybug regularly, by inspecting underneath calyces and thereby determining percentage of fruit infested. The most effective way of doing this is to break the fruit off from the calyx. Both the fruit and the underside of the calyx should then be inspected. Where mealybug is under good biocontrol, infestation should peak during December in the northern pro- duction areas and during January in the Cape production areas. If mealybug infestation does not decline during January and Febru- ary, respectively, suppression with a chemi- cal treatment is advisable on early maturing cultivars. Trial results have demonstrated that buprofezin (Applaud) is by far the most effective corrective option for mealybug con- trol. It is imperative that any application of buprofezin be targeted against the younger stages of mealybug, i.e. eggs, crawlers and second instars. Where buprofezin cannot be used, methomyl and chlorpyrifos can be used if preharvest intervals allow.This is also a good time to determine which species of mealybug are present. This is important, as it appears that the biocon- trol complexes of oleander mealybug and longtailed mealybug, in particular, might not be as effective as those of citrus mealybug. Therefore, treatments can be applied more readily when either of these species is identi- fied as the dominant species in a particular orchard. The phytosanitary status of certain species must also be borne in mind.False codling moth S.D. MOORE Effective false codling moth (FCM) control begins in November or even October with diligent orchard sanitation and the applica- tion of a registered control treatment. Follow up treatments should be applied as often asnecessary, bearing in mind that there is zero tolerance for FCM by certain markets, mak- ing the decision a phytosanitary one rather than an economic one. It is also imperative to refrain from using broad-spectrum long-re- sidual pesticides (most often used for thrips control) as early as possible in the season. Naturally occurring egg parasitoids can be extremely effective in reducing FCM levels and one should therefore conserve them.Granulovirus products (Cryptogran, Cryp- tex and Gratham), Delegate and Broadband (a new registration (Beauveria bassiana)) are the only pesticide sprays for FCM, which are per- mitted in all markets. The granuloviruses can be used up until the day of harvesting, whereas Delegate has a 7-day withholding period. A virus application should be applied shortly after a peak in FCM activity, determined by the use of a pheromone trap. However, this may be difficult to determine late in the sea- son when FCM levels are low and generations are overlapping. Note that due to high levels of UV irradiation in the Clanwilliam and Piket- berg magisterial districts of the Western Cape and in the Northern Cape, problems may be experienced with the efficacy of virus applied in these areas during February and March. The use of Cryptogran should therefore ideally be used in these areas before the beginning of De- cember and again after March. This problem does not exist in the rest of the country and therefore the caution is limited to the above- mentioned areas.Delegate is registered as a double-applica- tion, 8 and 4 weeks before harvest. However, even a single application will have a good ef- fect. Coragen (Rynaxypyr) also has a 7-day withholding period for most markets, bar Japan and Taiwan, where 90% petal drop ap- plies, albeit only for Mandarins in the case of Japan. Coragen is recommended to be ap- plied once or twice, from as early as 16 weeksbefore harvest and never at more than 8 500 L per hectare. Runner is registered to be ap- plied not more than twice in a season and has a withholding period of 30 days for all mar- kets except Taiwan. Bear in mind that the use of triflumuron (Alsystin) and teflubenzuron (Nomolt) is restricted to not later than 90% petal fall for several important markets, mak- ing them relatively ineffective for protection of the in-season crop. Also note that the with- holding period for fenpropathrin (Meothrin), which is 28 days for most markets, is 185 days for certain markets and cultivars. Cyperme- thrin (other than alpha- and zeta-cyperme- thrin) is not allowed on fruit destined for the USA market, but is permitted in other mar- kets with a withholding period of 28 days.Broadband is registered to be sprayed no fewer than three times in a season. It is sug- gested that if growers wish to use this prod- uct, that they should only do so within an integrated programme, as the efficacy of the product alone may not be sufficient.In addition to the insecticides, there are two mating disruption products – Isomate and Checkmate – and an attract and kill product, namely Last-Call FCM. However, all of these products are most effective when their use is initiated early in the season while FCM levels are still low. If this has not been done, initiation of their use late in the season is not recommended. Additionally, as the weather cools towards autumn, these phero- mone-based products may become less effec- tive due to a reduction in release rate. In such a case it may be necessary to follow up these treatments with a spray for FCM.Early maturing mandarins, such as Satsumas, which will be harvested during March, should be strongly considered for a registered spray treatment for FCM during February, i.e. approximately four weeks be- fore harvest. An effective treatment at thisTECHNOLOGY 65 FEB | MARCH 2015