Experiments on the profitability of chemical black pod control in Papua New Guinea

Comparison of cuprous oxide and metalaxyl with mixtures of these fungicides for thecontrol of Phytophthora pod rot of cocoa

“…0; these cuprous oxide is generally preferred, Pemg only slightly less tenacious than Bordeaux mixture but much easier to pre-.pare (Hislop & Park, 1962). It has been found 10 give cost effective control of black pod in Brazil (Anon., 1978), Costa Rica (Newhall, and Papua New Guinea (McGregor, •%!, 1983b). As with all surface protectants cuprous oxide can be rapidly leached from ihe -:ees by heavy rains which occur frequently •n many cocoa growing countries and Gorenz "974) speculated that systemic fungicideŝ ight give more reliable control of black pod.…”

“…As with all surface protectants cuprous oxide can be rapidly leached from ihe -:ees by heavy rains which occur frequently •n many cocoa growing countries and Gorenz "974) speculated that systemic fungicideŝ ight give more reliable control of black pod. Metalaxyl (Ridomil, Ciba-Geigy) is the best ' the currently available systemic fungicides active against Oomycetes (McGregor, 1982, ' 9*53a) and gives good control of black pod [^McGregor, 1983b;Ward et al, 1981), cocoa l^jirk canker (Prior & Smith, 1982) and seedling 'Wi (McGregor, 1983c), all caused in apua New Gumtahy Phytophthora palmivora 'But!.) Butl.…”

“…These findings emphasize the importance of avoiding resistance. TTiere is no guarantee that metalaxyl resistance will appear with the monthly appli-cation schedules suggested in the past for black pod control (McGregor, 1983b), indeed metalaxyl was used continuously for Bremia control on lettuce for several years in the U.K. without any resistance problem being detected (G. A. Carter, personal communication). Nevertheless, although metalaxyl resistance has not yet been found on cocoa even when continuously sprayed for 2!4 years (A. J. McGregor, unpublished survey), it was considered timely to develop an effective control for black pod which would avoid metalaxyl resistance.…”

Biological Control of Oomycetous Plant Pathogens: A Review

“…In addition, Phytophthora and Pythium spp. were responsible for many pre-and post-harvest problems on fruits and vegetables, including brown rot of citrus (Cohen 1981a, b, 1982, Gutter 1983, and black pod of cocoa (McGregor 1983(McGregor , 1984. Recently, new diseases are emerging caused by these oomycetes; for example, severe rotting and blight of seedlings of soybean (Tomioka et al 2013), root rot disease of legumes (Gaulin et al 2007), etc.…”