Download presentation
Presentation is loading. Please wait.
Published byDerek Arnold Modified over 9 years ago
1
Unit 3: Corn Insect Diseases
2
European Corn Borer & Southwestern Corn Borer Can cause 3% yield loss/corn borer/plant Sweet corn 8% Bore Stalks Tassels Cobs Ear Mature larvae ~1” long (ECB),.4” long (SWCB)
3
Unit 3: Corn Insect Diseases Mature adult overwinters in stalks, stubble, cobs, etc. Pupate from April to July Emerge as moths 2-3 wks later Prevention Complete destruction of all winter cover substances Early planting Improves plant vigor & ability to withstand damage
4
Unit 3: Corn Insect Diseases Treatment Chemical applications Must get them before they bore into the stalk Sweet corn – may treat every 5d Bt corn How might it be managed
6
Unit 3: Corn Insect Diseases
7
Corn Rootworm Bore into seedlings & ruin bud or growing point Feed on roots of older, established corn Control Corn/SB crop rotation used to provide good control Beetles are laying eggs in the SB fields anticipating corn the next season
8
Unit 3: Corn Insect Diseases Use chemical treated seed and/or soil-applied insecticide Bt corn is also effective Don’t forget the refuge area! Why is it important Corn Earworm Causes the most direct damage to the ear ~2% of the corn crop is victim to this pest 1-2 generations/yr. in our area Maybe 7 in southern U.S.
9
Unit 3: Corn Insect Diseases Overwinters 1-9” in the soil (pupae stage) Moth emerges in spring Lay ~1000 eggs each Full grown larvae ~1/2” Eats developing kernels Entry point for molds, and other insects Prevention Plant varieties w/ heavy husk covers (protects ear)
10
Unit 3: Corn Insect Diseases Early tillage can also destroy the pupae before they have a chance to emerge Treatment Chemical treatment is effective, if you catch them before they get into the ear Chinch Bug Can destroy entire fields in severe cases Greatest risk is late-planted corn next to a small grain
11
Unit 3: Corn Insect Diseases Can migrate by foot from wheat in June/July as wheat begins to ripen Prevention Spray a barrier strip around the field for protection May be ineffective if they are able to fly Plant resistant varieties
12
Unit 3: Corn Insect Diseases Nematodes 10 species can cause damage in corn Root injury, poor plant color, stunted growth, reduced yields Symptoms of nematode damage can often be confused w/ other problems Root rot, nutritional deficiencies, climatic stresses Must have a soil analysis to determine
13
Unit 3: Corn Insect Diseases Weevils Most commonly infest stored grain May fly to the fields in the South and damage standing corn Heavy husks help prevent infestation Most species cannot or will not penetrate the husk to lay eggs Fumigation is the only way to treat infested corn
14
Unit 3: Corn Insect Diseases Cutworms Sporadic problem pests Cut plant off at the ground Nocturnal feeders Can be controlled w/ barrier chemical applications Armyworms Most damage on late-planted corn Most devour leaves, but also will damage growing point
Similar presentations
© 2024 SlidePlayer.com. Inc.
All rights reserved.