Integration of Maize Lethal Necrosis Disease Management in Crop/Livestock Intensification to Enhance Productivity of Smallholder Agricultural Production Systems in East Africa Bright Jumbo1, Lava Kumar2, Dan Makumbi1, Yangole Luhenda3 and M. Bekunda2 1International Maize and Wheat Improvement Centre (CIMMYT) 2International Institute of Tropical Agriculture (IITA) 3SELIAN Agricultural Research Institute June 30 to July 2, 2016 AfricaRISING Annual Planning Meeting, Dar Tanzania

Study Objectives Establish the incidence and prevalence of MLN in three key maize growing regions of Tanzania which fall under three different climatic categories, Arusha (wet most of the seasons), Dodoma (semi-Arid) and Manyara (intermediate), map the areas affected by MLN Establish MLN impact on yield and other agronomic traits Identify MLN tolerant maize varieties and test their adaptability

Geographic coverage Sub-Humid District (1610 to 2178 mts) Assessment of maize lethal necrosis in AfricaRISING target areas Sub-Humid District (1610 to 2178 mts) Geographic coverage Semi-Arid Districts (1261- 1527 mts) Medium elevation

Materials and Methods Two surveys were conducted in three regions (Manyara, Arusha and Dodoma) 130 farms were sampled, leaf samples from symptomatic plants were brought to lab for ELISA The surveys were done during short season and main season Hybrids were evaluated in 156 trials using alpha lattice design

MLN prevalence in 2015 crop season Widespread and expanding; incidence between 5 to >70%

Prevalence of maize lethal necrosis and maize streak in 2015 crop season (N = 130) Percent

Prevalence and incidence of maize lethal necrosis in 2015 crop season (N = 130) Percent incidence Babati Manyara Dodoma Arusha

Prevalence of maize lethal necrosis, maize streak virus and other viruses in 2015 crop season (N = 130)

MLN Survey Results by Seasons (Long Vs Short) Total fields assessed MLN prevalence % MLN incidence % MLN severity (mean) MSV prevalence % MSV incidence% MSV severity (mean) Short dry season (Feb – Mar) 34 79.4 19.8 2.3 44.1 15.6 2.7 Main rainy season (May-Jun) 126 69.0 24.9 2.4 45.2 11.5 2.5 Total/Mean 160 74.2 22.4 44.7 13.6 2.6

Survey results based on cropping systems   Number of fields MLN severity (mean) MLN incidence (%) MSV severity (mean) MSV incidence (%) Maize Sole crop 61 2.4 25 2.5 12.1 Maize inter cropped with legumes and cereals 99 2.3 22 2.6 11.8

MLN Survey Results by District Prevalence, incidence and severity of maize virus diseases during minor maize season (2015) Region District No. of fields Virus incidence (%) virus disease severity MLN prevalence MLN severity (%) MLN Incidence (%) MSV prevalence MSV severity MSV Incidence (%) Arusha Meru 8 60.4 2.7 100 2.5 35 7.5 2.8 29 Manyara Babati 10 20 2.1 90 2 17 30 Mbulu 5 23 2.3 80 2.2 40 13 Dodoma Kongwa 6 2.4 66.6 4 33.3 3 Mpwapwa 7 57.1 42.8 Total   36 23.8 78.7 15.8 30.8 11.8 Note: In each field 30 plants were assessed; MSV = maize streak virus; MLN = maize lethal necrosis; incidence is expressed as % infected plants of the total plants assessed; and symptom severity is assessed based on 1 to 5 rating scale, where 1 = no symptoms and 5 = most severe symptoms

MLN Survey Results by District Incidence and severity of maize viruses on various cultivars observed during minor maize season surveys (2015) based on Variety Variety Total fields observed Virus incidence (%) Mean severity MLN Incidence (%) MLN severity MSV Incidence (%) MSV severity Local 12 14 2 11 3 1 SC627 5 15 STAHA 8 6 Stuka 33 10 23 TMV-1 unknown 68 40 27 DK8031 22 Kaspino 60 2.6 53 2.4 7 3.5 Kiboseed 5013 73 2.7 3.1 2.2 Pannar 2.3 2.5 SC719 37 Note: In each field 30 plants were assessed; MSV = maize streak virus; MLN = maize lethal necrosis; incidence is expressed as % infected plants of the total plants assessed; and symptom severity is assessed based on 1 to 5 rating scale, where 1 = no symptoms and 5 = most severe symptoms

MLN Survey Results by growing period (months)   Number of fields MLN severity (mean) MLN incidence (%) MSV severity (mean) MSV incidence (%) 1 to 2 months 18 2.3 25 2.2 9.3 2 to 3 months 127 23.1 2.6 12.6 >3 months 9 2.4 27.8 2.5 16.7

Table1. Maize Yield Losses Associated with MLN-Babati Pedigree Grain Yield (tha-1)† (tha-1) MLN   Percent Drop in Yield (%) Ear Aspect (1-5) Number of Plants plot-1 SYN(B)F2-5-8/CML539/CML442 7.6 2 73.7 2.8 22 18 SYN(B)F2-17-1/CML539/CML442 7.2 2.2 69.4 3 14 SYN(B)F2-14-3/CML539/CML442 7.1 1.8 74.6 2.7 15 SYN(B)F2-17-4/CML539/CML442 69.0 16 SYN(B)F2-19-4/CML539/CML442 1.6 77.5 SYN(B)F2-11-11/CML539/CML442 2.4 SYN(B)F2-5-5/CML539/CML442 7.0 2.9 58.6 3.4 SYN(B)F2-23-5/CML539/CML442 2.1 70.0 SYN(B)F2-22-3/CML539/CML442 1.4 80.0 3.3 21 13 SYN(B)F2-5-1/CML539/CML442 1.5 78.6 3.6 12 SYN(B)F2-5-4/CML539/CML442 1.1 84.3 3.5 SYN(B)F2-14-13/CML539/CML442 1.3 81.4 2.6 4 17 SYN(B)F2-9-1/CML539/CML442 6.9 78.3 SYN(B)F2-6-6/CML539/CML442 2.5 63.8 3.2 SYN(B)F2-12-2/CML539/CML442 84.1 4.1 8 SYN(B)F2-12-3/CML539/CML442 81.2 11 SYN(B)F2-17-3/CML539/CML442 71.0 3.1 SYN(B)F2-14-14/CML539/CML442 6.8 1.7 75.0 SYN(B)F2-7-1/CML539/CML442 67.6 SYN(B)F2-7-3/CML539/CML442 SYN(B)F2-11-8/CML539/CML442 0.4 94.1 Comercial Check 6.0 0.9 85.0 3.0 4.2 Experiment Mean 6.4 1.60 LSD (0.05) 2.3 1.33* 42.2 0.8 1.1* CV 18.8 41.85 13.6 16.0 30

Number of plants per row Table 2. Mean Grain yield and other important agronomic traits for the top performing hybrids among several hybrids evaluated in 56 Trials at Mara Farm in Babati under natural MLN infestation. Pedigree Grain Yield †(thha-1) Ears plant-1 Ear Rot (%) Number of plants per row Ear Aspect ‡1-5 scale CKH140117 2.4 1.1 50 13.9 3.5 CKH140098 1.9 0.8 63 16.6 CKH140107 59 11.9 CKH140031 1.7 1 74 12.1 3.7 CKH140105 72 13 CKH140035 1.6 0.7 67 11.5 CKH140017 1.5 0.9 71 CKH140106 1.3 1.2 80 14 CKH140124 85 12.4 4.2 CKH140032 79 4 CKH140018 70 13.4 CKH140003 98 12.3 5 CKH140015 66 12.8 CKH140011 0.6 56 11.8 4.5 H513 0.3 0.1 -1 7 H520 0.0 0.2 97 12.2 Experiment Mean 0.48 0.68 83.7 12 LSD (0.05) 1.34* 0.55** 31.9* 4.8*** 1.2NS CV 139.71 40.6 18.1 20 13.1 Num Reps 2 *Significant at P<0.05, **P<0.01, ***P<0.001; †Tons per hectare; ‡1 = good, 5=worse. Highlighted in blue are commercial checks.

More data this season We have hybrids still in 26 trials We plan to perform combined analysis for all the data from evaluation based on same trial

Summary MLN is a complex issue that requires integrated efforts involving researchers, maize producers, seed suppliers, policy makers, crop regulatory authorities to work together for measures to be effective We need an integrated and comprehensive approach that includes use of host resistance, strong sensitization on importance of using certified seed, applying good agricultural management practices, good pest management, inspection of fields to remove diseased plants at early stages, encouraging crop rotation and timely planting

Lets all joins hands and work together to defeat MLN and keep maize healthy! Thank you!