DEVELOPMENT AND EMERGENCE OF SITOTROGA CEREALELLA (OLIVER) ON STORED YELLOW MAIZE GENOTYPES AS AFFECTED BY PHYSICAL FACTORS AND GRAIN QUALITY

Angoumois Grain Moth, Sitotroga cerealella (Olivier) (Lepidoptera:Gelechiidae) is a serious primary pest of stored grain in many parts of the world. A study was carried out in the laboratory to investigate the effects of grain physical and intrinsic properties, temperature, relative humidity, and grain moisture content on the development and emergence of S. cerealella. The experiment was arranged in completely randomized design with three replicates for each maize genotypes used. Daily temperatures and relative humidity were recorded at 8:00 and 16:00 GMT with a Temperature and Humidity Sensor, which was embedded in the polypropylene bag containing six maize genotypes and tied after each reading to prevent emerging insects from escaping. The number of S. cerealella that emerged was observed weekly. Angoumois grain moth emergence on stored husked maize ears began in the 3rd week through to the 6th week in storage. The moth emergence was higher in the season with higher percentage grain moisture content. A significant (P<0.05) difference was observed in percentage grain moisture within almost all the same genotypes during both major and minor seasons. Aburokokoo, Ahoodzin, and Obatanpa had significantly (P<0.05) higher mean numbers of the emerged moth from the 4th to 6th week. The grain physical and intrinsic characteristics such as surface area and weight of Aburokokoo, Ahoodzin, and Obatanpa were statistically different (P<0.05) from the other three genotypes. A significant positive relationship was observed between grain surface area, grain weight, density and total S. cerealella emerged. Abontem, Honampa, and GH2354 with smaller grain surface area and lower grain weight had smaller mean number of the moth emerging. Anthocoris nemorum (L.) an important generalist agricultural pest predator was observed to be associated with the moth when its population was high (13-63) but none when the moth population was very small (0-4) in store. The association between mean daily temperatures and relative humidity during the 6 weeks storage in both seasons was inversely proportional. About 88.25% of the variation in relative humidity depends on temperature.

谷斑麦蛾（Angoumois Grain Moth，Sitotroga cerealella (Olivier)）隶属于鳞翅目（Lepidoptera）织蛾科（Gelechiidae），是全球多数地区储粮的关键性初级害虫。本研究于实验室条件下开展，旨在探究粮粒物理特性、内在属性、温度、相对湿度及粮粒含水量对Sitotroga cerealella生长发育与羽化的影响。实验采用完全随机设计，所用的6个玉米基因型均设置3次重复。每日于格林尼治标准时间（GMT）8:00与16:00，通过嵌入装有6个玉米基因型的聚丙烯袋（polypropylene bag）内的温湿度传感器（Temperature and Humidity Sensor）记录温湿度，每次读取数据后均系紧袋口，以防羽化后的成虫逃逸。研究人员每周统计羽化的Sitotroga cerealella数量。储粮去苞叶玉米果穗上的谷斑麦蛾羽化始见于储藏第3周，持续至第6周。粮粒含水量较高的储藏季，麦蛾羽化率显著更高。在主季与副季中，几乎所有相同玉米基因型的粮粒含水量均存在显著性差异（P<0.05）。Aburokokoo、Ahoodzin及Obatanpa在第4至6周的平均羽化蛾量显著（P<0.05）高于其余基因型。Aburokokoo、Ahoodzin及Obatanpa的粮粒物理与内在特征（如表面积与重量）与其余3个基因型存在统计学显著性差异（P<0.05）。粮粒表面积、粮粒重量及密度与总羽化蛾量之间呈显著正相关关系。Abontem、Honampa及GH2354的粮粒表面积更小、粮粒重量更低，其平均羽化蛾量也相应更少。暗色花蝽（Anthocoris nemorum (L.)）作为重要的广食性农业害虫天敌，在储粮蛾类种群密度处于13~63头时与其存在伴生关系，而当蛾类种群密度极低（0~4头）时则无此伴生现象。两个储藏季中，6周储藏期内的日均温与相对湿度呈负相关关系。相对湿度约88.25%的变异可由温度解释。