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The production of agricultural commodities faces increased risk of pests, diseases and other stresses due to climate change and variability. This study assesses the potential distribution of agricultural pests under projected climatic scenarios using evidence from the African coffee white stem borer (CWB), Monochamus leuconotus (Pascoe) (Coleoptera: Cerambycidae), an important pest of coffee in Zimbabwe. A species distribution modeling approach utilising Boosted Regression Trees (BRT) and Generalized Linear Models (GLM) was applied on current and projected climate data obtained from the WorldClim database and occurrence data (presence and absence) collected through on-farm biological surveys in Chipinge, Chimanimani, Mutare and Mutasa districts in Zimbabwe. Results from both the BRT and GLM indicate that precipitation-related variables are more important in determining species range for the CWB than temperature related variables. The CWB has extensive potential habitats in all coffee areas with Mutasa district having the largest model average area suitable for CWB under current and projected climatic conditions. Habitat ranges for CWB will increase under future climate scenarios for Chipinge, Chimanimani and Mutare districts while it will decrease in Mutasa district. The highest percentage change in area suitable for the CWB was for Chimanimani district with a model average of 49.1% (3 906 ha) increase in CWB range by 2080. The BRT and GLM predictions gave similar predicted ranges for Chipinge, Chimanimani and Mutasa districts compared to the high variation in current and projected habitat area for CWB in Mutare district. The study concludes that suitable area for CWB will increase significantly in Zimbabwe due to climate change and there is need to develop adaptation mechanisms.

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Fall armyworm [Spodoptera frugiperda (J.E. Smith); FAW] invasion has exacerbated maize (Zea mays L.) crop yield losses in sub‐Saharan Africa (SSA), already threatened by other stresses, especially those that are climate‐change induced. The FAW is difficult to control, manage, or eradicate, because it is polyphagous and trans‐boundary, multiplies fast, has a short life cycle and migrates easily, and lacks the diapause growth phase. In this study, FAW and its impact in Africa was reviewed, as well as past and present control strategies for this pest. Pesticides, cultural practices, natural enemies, host‐plant resistance, integrated pest management (IPM), and plant breeding approaches were examined as possible control strategies. It was concluded that an IPM control strategy, guided by cultural approaches already being used by farmers, and what can be adopted from the Americas, coupled with an insect‐resistance management strategy, is the best option to manage this pest in Africa. These strategies will be strengthened by breeding for multi‐trait host‐plant resistance through stacking of genes for different modes of control of the pest.

A study was conducted to evaluate four common coffee (Coffea arabica) varieties in Zimbabwe for drought tolerance and ability to recover. The plants were subjected to drought stress for 21 and 28 days with evaluation of recovery done 14 days after interruptive irrigation. Coffee varieties were not significantly different in initial fresh and dry biomass before stressing (P>0.05). CR95 had significantly accumulated more (P<0.05)dry root mass (0.8 g) than the rest of the varieties after 21 days of drought stress. SL28 and CR95 had an 8.3% increase in dry biomass while Cat128 did not gain any dry biomass after 21 days of drought stress. CR95 had significantly more (P<0.05) total dry biomass after 21 days and 28 days of drought stress while SL28 was consistently the least in both periods. Cat129 had the highest recovery gains in dry root, dry shoot, and total dry biomass after 21 days and 28 days of drought stress. Initial root biomass was negatively correlated with changes in total fresh and dry biomass of young coffee (r>0.60) after both 21 and 28 days of drought stress, indicating that root biomass may be the most important factor determining drought tolerance in coffee varieties.

Fall armyworm [Spodoptera frugiperda (J./E. Smith); FAW] is negatively impacting sustainable maize production, particularly in smallholder farming systems in sub-Saharan Africa. Two sets of germplasm (commercial cultivars and experimental hybrids, and local and exotic inbred lines) were evaluated under managed and natural FAW infestation to identify FAW tolerant material with superior grain yield performance. Significant genotypic effects on foliar FAW damage, ear FAW damage, and grain yield were observed. Commercial cultivars were significantly more affected by FAW infestation than experimental hybrids, as evidenced by high foliar and ear damage scores, yet they out-yielded experimental genotypes. The introduced FAW donor lines (CML338, CML67, CML121, and CML334) showed better tolerance to FAW, individually and in hybrid combinations. Local inbred lines, SV1P, CML491, and CML 539, also showed FAW tolerance. Hybrids and open pollinated varieties were more vulnerable to FAW damage at early growth stages, but they grew out of it through the mid to late whorl stages. Inbred lines showed increasing damage as they grew to maturity. Husk cover, ear rot, anthesis date, and plant height were highly correlated with FAW tolerance. The identified local and exotic lines with FAW tolerance will contribute to FAW resistance breeding in southern Africa.

Inadequate information is available on trait relations and profiles of sorghum genotypes, yet this information is vital for precise decisions to be undertaken in breeding programs. Here, 17 sorghum experimental lines were evaluated together with three checks at five locations, representing the major sorghum production environments in Zimbabwe. Across site analysis of variance (ANOVA) showed significant genotypic effects on grain yield (GYD) as well as the other traits, including panicle length (PL) and stem diameter (SD). Distance-based clustering indicated the possibility of indirectly selecting for GYD using; SD, exertion (EXSTN), panicle length (PL), panicle width (PW) and number of leaves (NL). In addition, the vector view of the genotype-by-trait (GT) biplot also revealed strong correlations between GYD and, PW, SD and FYD, as well as the other physiological traits including, days to male flowering (DMA) and days to physiological maturity (DPM). Genotypes superior for a combination of traits were, G6, G7, G11, G18 and G20, which were strong for GYD, PL and PW, as well as, G5 which was strong for sugar content (SC), number of leaves (NL) and SD. Genotypes 15, 16 and 17, were specifically strong for GYD whereas, genotypes 4 and 9 were strong for FYD. Overall, results revealed the key traits which can be considered singularly or in combination, when selecting suitable sorghum genotypes, either for feed or food purposes, under arid and semi-arid conditions. This information is vital for decision making in sorghum breeding programs.

Cotton is a very important crop that consists of traits with different associationship due to genetic and environmental factors. In order to determine the degree of association between seed cotton yield and important traits, a study was done using an RCBD experiment with ten genotypes. Seed cotton yield, GOT, lint yield, boll weight, bolls per plant, seed weight, plant height, fibre length, elongation, fineness and strength data were collected and analysed. Genotypic and phenotypic correlation analysis was done in Meta R. Estimation of direct and indirect effects was done using path analysis in Microsoft Excel. Analysis of variance revealed significant differences for boll weight, seed weight, GOT and plant height. Seed cotton yield was correlated with lint yield (r = 0.71***), fibre elongation (r = 0.54***), bolls per plant (0.27***), seed weight (r = 0.22***), strength (r = 0.21***) and fineness (r = 0.13*) at genotypic level. Ginning outturn was correlated with lint yield (r = 0.70***), elongation (r = 0.60***) and strength (r = 0.50***). Boll weight was correlated with seed weight (r = 0.56***) whilst plant height was highly associated with fibre strength (r = 0.58***). The adjusted R Square (0.98), low standard error (0.12) and low residual effect (R = 0.01) in regression analysis indicated that ABOUT THE AUTHOR Chapepa Blessing is a plant breeder working at Cotton Research Institute of Zimbabwe as a cotton breeder. His research areas are developing, implementation analyzing data and information dissemination of the national cotton breeding program in the Department of Research and Specialist Services of the Ministry of Agriculture in the country. Other research interests include crop modelling using remote sensing technology and molecular tool applications. Marco Mare is also plant breeder at Cotton Research Institute and is involved in developing, implementation analyzing data and information dissemination of the national cotton breeding program. Washington Mubvekeri is the head of Cotton Research Institute and is responsible for all cotton research programs in the country.