The first of May in upstate New York usually finds fields plowed, corn planted and apple trees sprouting leaves. But this year's record April rainfall -- 7.31 inches in Ithaca, more than double the 3.29-inch 30-year average, according to the Northeast Regional Climate Center -- has resulted in wet soils impassible for farm equipment.

While farmers eye the weather forecasts, Cornell's crop production experts are looking to the season-long challenges ahead, which could include planting delays, scabby apples, stressed strawberries and hurried bees.

"Growers are nervous and frustrated," said Stephen Reiners, associate professor of horticultural sciences at the New York State Agricultural Experiment Station (NYSAES) in Geneva, N.Y., who works closely with state vegetable farmers. "Growers of cool season crops like broccoli, spinach and peas have to plant early to avoid summer heat, and we may see a delayed harvest this year. If rain continues into May, growers may opt to forgo planting them entirely this year."

How dry is dry enough for a tractor? According to William Cox, professor of soil and crop sciences, it can take a full week without rain for soils to dry out, so the early May weather will be crucial for many crops.

For row crops like field corn and soybeans, Cox describes the situation as annoying but not dire. And his research on planting dates should be reassuring for farmers nervous about planting their field corn in May. He has found that the yield of corn planted up until May 20 equals that of corn planted in late April.

"It's better to plant on dry soils on May 25 than on wet soils on May 10, because of the risk of compacting the soil," said Cox. "And if the wet weather continues well into May, farmers have the option of planting a short-season corn variety that can still mature in time."

For other crops, the effects of the rain could last through summer. According to Kerik Cox, assistant professor of plant pathology at NYSAES, inadequate root development in raspberries and strawberries now could manifest as plant stress during drier, hotter weather later in the season.

In the area's apple orchards, the rain has favored an unwanted guest: apple scab, a fungus that causes lesions on apple leaves and fruit. According to plant pathologist Cox, limited spraying coupled with the increased disease pressure will make 2011 a tough year for producing picture-perfect apples.

"Usually farmers apply their first, protective sprays in April when the trees leaf out, and the fungus is initially producing spores," said Cox. "Fungicides need to dry on foliage to be effective, and the constant rainfall has prevented successful application. Also, because the rain washes off the fungicides, every few inches of rain may require another pass through the orchard, and farmers simply haven't been able to do that because of the wet soil."

Cox says that without timely control, apple scab will cause scabby lesions on leaves and developing fruit, rendering the crop edible, but not marketable because of industry preference for pristine fresh fruit. Cox advises growers to focus on fungicides most effective on apple scab, rather than for diseases that thrive in drier weather.

The rainfall also affects insects -- crop friends and foes alike.

"Early season insect pests are actually deterred in their egg laying by the rain, and in some cases they are a week or more behind normal development," said entomology professor Arthur Agnello. "However, if the rain continues into May, bees may not be as able to effectively pollinate all the fruit blossoms, so growers will need to take this into account when deciding how much thinning is required."

Amanda Garris is a freelance writer in Geneva, N.Y.

This year has so far been the second-wettest on record in Ithaca with 15.95 inches of rain since January, according to the Northeast Regional Climate Center; and rainfall has topped the charts in several nearby cities.

Cities that have seen record rainfall since January are Binghamton (19.08 inches), Harrisburg, Pa. (19.30 inches), Scranton, Pa. (16.95 inches), Williamsport, Pa. (22.76 inches) and Burlington, Vt. (15.73 inches).

April has been the rainiest on record for Rochester (5.81 inches), Syracuse (8.53 inches), Harrisburg (9.46 inches), Williamsport (10.04 inches), Burlington (7.88 inches) and Huntington, W.Va. (9.98 inches), according to the data.

Ithaca recorded its rainiest January to April in 1958 with 15.97 inches. The wettest April was in 1993 with 8.16 inches, compared with its second-wettest April this year with 7.31 inches of rain.

-- Lauren Gold