Maize growers looking for reversal

Unprecedented levels of rain from the ve cyclones that lashed the Bay of Plenty in one year, have meant that the growing degree days of maize (GDDS) have not been su cient to provide the energy for the accumulation of dry matter (DM) in either the stover or the cob.

A growing degree day measures the amount of heat accumulated over a period, usually 24 hours. Maize hybrids can di er in their requirements for heat and sunlight to attain maximum production.

“Hybrid maturities can be associated with de nite amounts of GDDS required from planting to physiological maturity. Maize hybrids considered to be mid-maturity in the Bay of Plenty/Waikato region require approximately 2600 GDDS and given the weather this season, we were well short of the GDDS required to maximise quality and yield potential,” says VP Maxx account manager Barry Smallridge. e continued wet and moderate conditions made the perfect breeding ground for Northern Leaf Blight. NLB can be identi ed by a yellow border (transparent when held to the light), which surrounds various shaped lesions that have irregular margins.

“In maize, premature plant death during grain ll can result in signi cant yield losses. e amount of yield loss depends on the severity of the injury and the growth stage when the injury occurred.

“In silage, the loss of leaves through NLB at the soft dough stage, which is prior to